summaryrefslogtreecommitdiffstats
path: root/kopete/plugins/statistics/sqlite/select.c
diff options
context:
space:
mode:
authortoma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da>2009-11-25 17:56:58 +0000
committertoma <toma@283d02a7-25f6-0310-bc7c-ecb5cbfe19da>2009-11-25 17:56:58 +0000
commitbcb704366cb5e333a626c18c308c7e0448a8e69f (patch)
treef0d6ab7d78ecdd9207cf46536376b44b91a1ca71 /kopete/plugins/statistics/sqlite/select.c
downloadtdenetwork-bcb704366cb5e333a626c18c308c7e0448a8e69f.tar.gz
tdenetwork-bcb704366cb5e333a626c18c308c7e0448a8e69f.zip
Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.
BUG:215923 git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdenetwork@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da
Diffstat (limited to 'kopete/plugins/statistics/sqlite/select.c')
-rw-r--r--kopete/plugins/statistics/sqlite/select.c2628
1 files changed, 2628 insertions, 0 deletions
diff --git a/kopete/plugins/statistics/sqlite/select.c b/kopete/plugins/statistics/sqlite/select.c
new file mode 100644
index 00000000..8bee7897
--- /dev/null
+++ b/kopete/plugins/statistics/sqlite/select.c
@@ -0,0 +1,2628 @@
+/*
+** 2001 September 15
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+*************************************************************************
+** This file contains C code routines that are called by the parser
+** to handle SELECT statements in SQLite.
+**
+** $Id$
+*/
+#include "sqliteInt.h"
+
+
+/*
+** Allocate a new Select structure and return a pointer to that
+** structure.
+*/
+Select *sqlite3SelectNew(
+ ExprList *pEList, /* which columns to include in the result */
+ SrcList *pSrc, /* the FROM clause -- which tables to scan */
+ Expr *pWhere, /* the WHERE clause */
+ ExprList *pGroupBy, /* the GROUP BY clause */
+ Expr *pHaving, /* the HAVING clause */
+ ExprList *pOrderBy, /* the ORDER BY clause */
+ int isDistinct, /* true if the DISTINCT keyword is present */
+ int nLimit, /* LIMIT value. -1 means not used */
+ int nOffset /* OFFSET value. 0 means no offset */
+){
+ Select *pNew;
+ pNew = sqliteMalloc( sizeof(*pNew) );
+ if( pNew==0 ){
+ sqlite3ExprListDelete(pEList);
+ sqlite3SrcListDelete(pSrc);
+ sqlite3ExprDelete(pWhere);
+ sqlite3ExprListDelete(pGroupBy);
+ sqlite3ExprDelete(pHaving);
+ sqlite3ExprListDelete(pOrderBy);
+ }else{
+ if( pEList==0 ){
+ pEList = sqlite3ExprListAppend(0, sqlite3Expr(TK_ALL,0,0,0), 0);
+ }
+ pNew->pEList = pEList;
+ pNew->pSrc = pSrc;
+ pNew->pWhere = pWhere;
+ pNew->pGroupBy = pGroupBy;
+ pNew->pHaving = pHaving;
+ pNew->pOrderBy = pOrderBy;
+ pNew->isDistinct = isDistinct;
+ pNew->op = TK_SELECT;
+ pNew->nLimit = nLimit;
+ pNew->nOffset = nOffset;
+ pNew->iLimit = -1;
+ pNew->iOffset = -1;
+ }
+ return pNew;
+}
+
+/*
+** Given 1 to 3 identifiers preceeding the JOIN keyword, determine the
+** type of join. Return an integer constant that expresses that type
+** in terms of the following bit values:
+**
+** JT_INNER
+** JT_OUTER
+** JT_NATURAL
+** JT_LEFT
+** JT_RIGHT
+**
+** A full outer join is the combination of JT_LEFT and JT_RIGHT.
+**
+** If an illegal or unsupported join type is seen, then still return
+** a join type, but put an error in the pParse structure.
+*/
+int sqlite3JoinType(Parse *pParse, Token *pA, Token *pB, Token *pC){
+ int jointype = 0;
+ Token *apAll[3];
+ Token *p;
+ static const struct {
+ const char *zKeyword;
+ u8 nChar;
+ u8 code;
+ } keywords[] = {
+ { "natural", 7, JT_NATURAL },
+ { "left", 4, JT_LEFT|JT_OUTER },
+ { "right", 5, JT_RIGHT|JT_OUTER },
+ { "full", 4, JT_LEFT|JT_RIGHT|JT_OUTER },
+ { "outer", 5, JT_OUTER },
+ { "inner", 5, JT_INNER },
+ { "cross", 5, JT_INNER },
+ };
+ int i, j;
+ apAll[0] = pA;
+ apAll[1] = pB;
+ apAll[2] = pC;
+ for(i=0; i<3 && apAll[i]; i++){
+ p = apAll[i];
+ for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
+ if( p->n==keywords[j].nChar
+ && sqlite3StrNICmp(p->z, keywords[j].zKeyword, p->n)==0 ){
+ jointype |= keywords[j].code;
+ break;
+ }
+ }
+ if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
+ jointype |= JT_ERROR;
+ break;
+ }
+ }
+ if(
+ (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
+ (jointype & JT_ERROR)!=0
+ ){
+ const char *zSp1 = " ";
+ const char *zSp2 = " ";
+ if( pB==0 ){ zSp1++; }
+ if( pC==0 ){ zSp2++; }
+ sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
+ "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
+ jointype = JT_INNER;
+ }else if( jointype & JT_RIGHT ){
+ sqlite3ErrorMsg(pParse,
+ "RIGHT and FULL OUTER JOINs are not currently supported");
+ jointype = JT_INNER;
+ }
+ return jointype;
+}
+
+/*
+** Return the index of a column in a table. Return -1 if the column
+** is not contained in the table.
+*/
+static int columnIndex(Table *pTab, const char *zCol){
+ int i;
+ for(i=0; i<pTab->nCol; i++){
+ if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
+ }
+ return -1;
+}
+
+/*
+** Set the value of a token to a '\000'-terminated string.
+*/
+static void setToken(Token *p, const char *z){
+ p->z = z;
+ p->n = strlen(z);
+ p->dyn = 0;
+}
+
+
+/*
+** Add a term to the WHERE expression in *ppExpr that requires the
+** zCol column to be equal in the two tables pTab1 and pTab2.
+*/
+static void addWhereTerm(
+ const char *zCol, /* Name of the column */
+ const Table *pTab1, /* First table */
+ const Table *pTab2, /* Second table */
+ Expr **ppExpr /* Add the equality term to this expression */
+){
+ Token dummy;
+ Expr *pE1a, *pE1b, *pE1c;
+ Expr *pE2a, *pE2b, *pE2c;
+ Expr *pE;
+
+ setToken(&dummy, zCol);
+ pE1a = sqlite3Expr(TK_ID, 0, 0, &dummy);
+ pE2a = sqlite3Expr(TK_ID, 0, 0, &dummy);
+ setToken(&dummy, pTab1->zName);
+ pE1b = sqlite3Expr(TK_ID, 0, 0, &dummy);
+ setToken(&dummy, pTab2->zName);
+ pE2b = sqlite3Expr(TK_ID, 0, 0, &dummy);
+ pE1c = sqlite3Expr(TK_DOT, pE1b, pE1a, 0);
+ pE2c = sqlite3Expr(TK_DOT, pE2b, pE2a, 0);
+ pE = sqlite3Expr(TK_EQ, pE1c, pE2c, 0);
+ ExprSetProperty(pE, EP_FromJoin);
+ *ppExpr = sqlite3ExprAnd(*ppExpr, pE);
+}
+
+/*
+** Set the EP_FromJoin property on all terms of the given expression.
+**
+** The EP_FromJoin property is used on terms of an expression to tell
+** the LEFT OUTER JOIN processing logic that this term is part of the
+** join restriction specified in the ON or USING clause and not a part
+** of the more general WHERE clause. These terms are moved over to the
+** WHERE clause during join processing but we need to remember that they
+** originated in the ON or USING clause.
+*/
+static void setJoinExpr(Expr *p){
+ while( p ){
+ ExprSetProperty(p, EP_FromJoin);
+ setJoinExpr(p->pLeft);
+ p = p->pRight;
+ }
+}
+
+/*
+** This routine processes the join information for a SELECT statement.
+** ON and USING clauses are converted into extra terms of the WHERE clause.
+** NATURAL joins also create extra WHERE clause terms.
+**
+** The terms of a FROM clause are contained in the Select.pSrc structure.
+** The left most table is the first entry in Select.pSrc. The right-most
+** table is the last entry. The join operator is held in the entry to
+** the left. Thus entry 0 contains the join operator for the join between
+** entries 0 and 1. Any ON or USING clauses associated with the join are
+** also attached to the left entry.
+**
+** This routine returns the number of errors encountered.
+*/
+static int sqliteProcessJoin(Parse *pParse, Select *p){
+ SrcList *pSrc; /* All tables in the FROM clause */
+ int i, j; /* Loop counters */
+ struct SrcList_item *pLeft; /* Left table being joined */
+ struct SrcList_item *pRight; /* Right table being joined */
+
+ pSrc = p->pSrc;
+ pLeft = &pSrc->a[0];
+ pRight = &pLeft[1];
+ for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
+ Table *pLeftTab = pLeft->pTab;
+ Table *pRightTab = pRight->pTab;
+
+ if( pLeftTab==0 || pRightTab==0 ) continue;
+
+ /* When the NATURAL keyword is present, add WHERE clause terms for
+ ** every column that the two tables have in common.
+ */
+ if( pLeft->jointype & JT_NATURAL ){
+ if( pLeft->pOn || pLeft->pUsing ){
+ sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
+ "an ON or USING clause", 0);
+ return 1;
+ }
+ for(j=0; j<pLeftTab->nCol; j++){
+ char *zName = pLeftTab->aCol[j].zName;
+ if( columnIndex(pRightTab, zName)>=0 ){
+ addWhereTerm(zName, pLeftTab, pRightTab, &p->pWhere);
+ }
+ }
+ }
+
+ /* Disallow both ON and USING clauses in the same join
+ */
+ if( pLeft->pOn && pLeft->pUsing ){
+ sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
+ "clauses in the same join");
+ return 1;
+ }
+
+ /* Add the ON clause to the end of the WHERE clause, connected by
+ ** an AND operator.
+ */
+ if( pLeft->pOn ){
+ setJoinExpr(pLeft->pOn);
+ p->pWhere = sqlite3ExprAnd(p->pWhere, pLeft->pOn);
+ pLeft->pOn = 0;
+ }
+
+ /* Create extra terms on the WHERE clause for each column named
+ ** in the USING clause. Example: If the two tables to be joined are
+ ** A and B and the USING clause names X, Y, and Z, then add this
+ ** to the WHERE clause: A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
+ ** Report an error if any column mentioned in the USING clause is
+ ** not contained in both tables to be joined.
+ */
+ if( pLeft->pUsing ){
+ IdList *pList = pLeft->pUsing;
+ for(j=0; j<pList->nId; j++){
+ char *zName = pList->a[j].zName;
+ if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
+ sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
+ "not present in both tables", zName);
+ return 1;
+ }
+ addWhereTerm(zName, pLeftTab, pRightTab, &p->pWhere);
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+** Delete the given Select structure and all of its substructures.
+*/
+void sqlite3SelectDelete(Select *p){
+ if( p==0 ) return;
+ sqlite3ExprListDelete(p->pEList);
+ sqlite3SrcListDelete(p->pSrc);
+ sqlite3ExprDelete(p->pWhere);
+ sqlite3ExprListDelete(p->pGroupBy);
+ sqlite3ExprDelete(p->pHaving);
+ sqlite3ExprListDelete(p->pOrderBy);
+ sqlite3SelectDelete(p->pPrior);
+ sqliteFree(p->zSelect);
+ sqliteFree(p);
+}
+
+/*
+** Delete the aggregate information from the parse structure.
+*/
+static void sqliteAggregateInfoReset(Parse *pParse){
+ sqliteFree(pParse->aAgg);
+ pParse->aAgg = 0;
+ pParse->nAgg = 0;
+ pParse->useAgg = 0;
+}
+
+/*
+** Insert code into "v" that will push the record on the top of the
+** stack into the sorter.
+*/
+static void pushOntoSorter(Parse *pParse, Vdbe *v, ExprList *pOrderBy){
+ int i;
+ for(i=0; i<pOrderBy->nExpr; i++){
+ sqlite3ExprCode(pParse, pOrderBy->a[i].pExpr);
+ }
+ sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr, 0);
+ sqlite3VdbeAddOp(v, OP_SortPut, 0, 0);
+}
+
+/*
+** Add code to implement the OFFSET and LIMIT
+*/
+static void codeLimiter(
+ Vdbe *v, /* Generate code into this VM */
+ Select *p, /* The SELECT statement being coded */
+ int iContinue, /* Jump here to skip the current record */
+ int iBreak, /* Jump here to end the loop */
+ int nPop /* Number of times to pop stack when jumping */
+){
+ if( p->iOffset>=0 ){
+ int addr = sqlite3VdbeCurrentAddr(v) + 2;
+ if( nPop>0 ) addr++;
+ sqlite3VdbeAddOp(v, OP_MemIncr, p->iOffset, addr);
+ if( nPop>0 ){
+ sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
+ }
+ sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
+ VdbeComment((v, "# skip OFFSET records"));
+ }
+ if( p->iLimit>=0 ){
+ sqlite3VdbeAddOp(v, OP_MemIncr, p->iLimit, iBreak);
+ VdbeComment((v, "# exit when LIMIT reached"));
+ }
+}
+
+/*
+** This routine generates the code for the inside of the inner loop
+** of a SELECT.
+**
+** If srcTab and nColumn are both zero, then the pEList expressions
+** are evaluated in order to get the data for this row. If nColumn>0
+** then data is pulled from srcTab and pEList is used only to get the
+** datatypes for each column.
+*/
+static int selectInnerLoop(
+ Parse *pParse, /* The parser context */
+ Select *p, /* The complete select statement being coded */
+ ExprList *pEList, /* List of values being extracted */
+ int srcTab, /* Pull data from this table */
+ int nColumn, /* Number of columns in the source table */
+ ExprList *pOrderBy, /* If not NULL, sort results using this key */
+ int distinct, /* If >=0, make sure results are distinct */
+ int eDest, /* How to dispose of the results */
+ int iParm, /* An argument to the disposal method */
+ int iContinue, /* Jump here to continue with next row */
+ int iBreak, /* Jump here to break out of the inner loop */
+ char *aff /* affinity string if eDest is SRT_Union */
+){
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ int hasDistinct; /* True if the DISTINCT keyword is present */
+
+ if( v==0 ) return 0;
+ assert( pEList!=0 );
+
+ /* If there was a LIMIT clause on the SELECT statement, then do the check
+ ** to see if this row should be output.
+ */
+ hasDistinct = distinct>=0 && pEList && pEList->nExpr>0;
+ if( pOrderBy==0 && !hasDistinct ){
+ codeLimiter(v, p, iContinue, iBreak, 0);
+ }
+
+ /* Pull the requested columns.
+ */
+ if( nColumn>0 ){
+ for(i=0; i<nColumn; i++){
+ sqlite3VdbeAddOp(v, OP_Column, srcTab, i);
+ }
+ }else{
+ nColumn = pEList->nExpr;
+ for(i=0; i<pEList->nExpr; i++){
+ sqlite3ExprCode(pParse, pEList->a[i].pExpr);
+ }
+ }
+
+ /* If the DISTINCT keyword was present on the SELECT statement
+ ** and this row has been seen before, then do not make this row
+ ** part of the result.
+ */
+ if( hasDistinct ){
+#if NULL_ALWAYS_DISTINCT
+ sqlite3VdbeAddOp(v, OP_IsNull, -pEList->nExpr, sqlite3VdbeCurrentAddr(v)+7);
+#endif
+ /* Deliberately leave the affinity string off of the following
+ ** OP_MakeRecord */
+ sqlite3VdbeAddOp(v, OP_MakeRecord, pEList->nExpr * -1, 0);
+ sqlite3VdbeAddOp(v, OP_Distinct, distinct, sqlite3VdbeCurrentAddr(v)+3);
+ sqlite3VdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
+ VdbeComment((v, "# skip indistinct records"));
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_PutStrKey, distinct, 0);
+ if( pOrderBy==0 ){
+ codeLimiter(v, p, iContinue, iBreak, nColumn);
+ }
+ }
+
+ switch( eDest ){
+ /* In this mode, write each query result to the key of the temporary
+ ** table iParm.
+ */
+ case SRT_Union: {
+ sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, NULL_ALWAYS_DISTINCT);
+ sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_PutStrKey, iParm, 0);
+ break;
+ }
+
+ /* Store the result as data using a unique key.
+ */
+ case SRT_Table:
+ case SRT_TempTable: {
+ sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
+ if( pOrderBy ){
+ pushOntoSorter(pParse, v, pOrderBy);
+ }else{
+ sqlite3VdbeAddOp(v, OP_NewRecno, iParm, 0);
+ sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
+ sqlite3VdbeAddOp(v, OP_PutIntKey, iParm, 0);
+ }
+ break;
+ }
+
+ /* Construct a record from the query result, but instead of
+ ** saving that record, use it as a key to delete elements from
+ ** the temporary table iParm.
+ */
+ case SRT_Except: {
+ int addr;
+ addr = sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, NULL_ALWAYS_DISTINCT);
+ sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
+ sqlite3VdbeAddOp(v, OP_NotFound, iParm, addr+3);
+ sqlite3VdbeAddOp(v, OP_Delete, iParm, 0);
+ break;
+ }
+
+ /* If we are creating a set for an "expr IN (SELECT ...)" construct,
+ ** then there should be a single item on the stack. Write this
+ ** item into the set table with bogus data.
+ */
+ case SRT_Set: {
+ int addr1 = sqlite3VdbeCurrentAddr(v);
+ int addr2;
+
+ assert( nColumn==1 );
+ sqlite3VdbeAddOp(v, OP_NotNull, -1, addr1+3);
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
+ if( pOrderBy ){
+ pushOntoSorter(pParse, v, pOrderBy);
+ }else{
+ char aff = (iParm>>16)&0xFF;
+ aff = sqlite3CompareAffinity(pEList->a[0].pExpr, aff);
+ sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &aff, 1);
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_PutStrKey, (iParm&0x0000FFFF), 0);
+ }
+ sqlite3VdbeChangeP2(v, addr2, sqlite3VdbeCurrentAddr(v));
+ break;
+ }
+
+ /* If this is a scalar select that is part of an expression, then
+ ** store the results in the appropriate memory cell and break out
+ ** of the scan loop.
+ */
+ case SRT_Mem: {
+ assert( nColumn==1 );
+ if( pOrderBy ){
+ pushOntoSorter(pParse, v, pOrderBy);
+ }else{
+ sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, iBreak);
+ }
+ break;
+ }
+
+ /* Send the data to the callback function.
+ */
+ case SRT_Callback:
+ case SRT_Sorter: {
+ if( pOrderBy ){
+ sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
+ pushOntoSorter(pParse, v, pOrderBy);
+ }else{
+ assert( eDest==SRT_Callback );
+ sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
+ }
+ break;
+ }
+
+ /* Invoke a subroutine to handle the results. The subroutine itself
+ ** is responsible for popping the results off of the stack.
+ */
+ case SRT_Subroutine: {
+ if( pOrderBy ){
+ sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
+ pushOntoSorter(pParse, v, pOrderBy);
+ }else{
+ sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
+ }
+ break;
+ }
+
+ /* Discard the results. This is used for SELECT statements inside
+ ** the body of a TRIGGER. The purpose of such selects is to call
+ ** user-defined functions that have side effects. We do not care
+ ** about the actual results of the select.
+ */
+ default: {
+ assert( eDest==SRT_Discard );
+ sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
+ break;
+ }
+ }
+ return 0;
+}
+
+/*
+** If the inner loop was generated using a non-null pOrderBy argument,
+** then the results were placed in a sorter. After the loop is terminated
+** we need to run the sorter and output the results. The following
+** routine generates the code needed to do that.
+*/
+static void generateSortTail(
+ Parse *pParse, /* The parsing context */
+ Select *p, /* The SELECT statement */
+ Vdbe *v, /* Generate code into this VDBE */
+ int nColumn, /* Number of columns of data */
+ int eDest, /* Write the sorted results here */
+ int iParm /* Optional parameter associated with eDest */
+){
+ int end1 = sqlite3VdbeMakeLabel(v);
+ int end2 = sqlite3VdbeMakeLabel(v);
+ int addr;
+ KeyInfo *pInfo;
+ ExprList *pOrderBy;
+ int nCol, i;
+ sqlite3 *db = pParse->db;
+
+ if( eDest==SRT_Sorter ) return;
+ pOrderBy = p->pOrderBy;
+ nCol = pOrderBy->nExpr;
+ pInfo = sqliteMalloc( sizeof(*pInfo) + nCol*(sizeof(CollSeq*)+1) );
+ if( pInfo==0 ) return;
+ pInfo->aSortOrder = (char*)&pInfo->aColl[nCol];
+ pInfo->nField = nCol;
+ for(i=0; i<nCol; i++){
+ /* If a collation sequence was specified explicity, then it
+ ** is stored in pOrderBy->a[i].zName. Otherwise, use the default
+ ** collation type for the expression.
+ */
+ pInfo->aColl[i] = sqlite3ExprCollSeq(pParse, pOrderBy->a[i].pExpr);
+ if( !pInfo->aColl[i] ){
+ pInfo->aColl[i] = db->pDfltColl;
+ }
+ pInfo->aSortOrder[i] = pOrderBy->a[i].sortOrder;
+ }
+ sqlite3VdbeOp3(v, OP_Sort, 0, 0, (char*)pInfo, P3_KEYINFO_HANDOFF);
+ addr = sqlite3VdbeAddOp(v, OP_SortNext, 0, end1);
+ codeLimiter(v, p, addr, end2, 1);
+ switch( eDest ){
+ case SRT_Table:
+ case SRT_TempTable: {
+ sqlite3VdbeAddOp(v, OP_NewRecno, iParm, 0);
+ sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
+ sqlite3VdbeAddOp(v, OP_PutIntKey, iParm, 0);
+ break;
+ }
+ case SRT_Set: {
+ assert( nColumn==1 );
+ sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
+ sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, "n", P3_STATIC);
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_PutStrKey, (iParm&0x0000FFFF), 0);
+ break;
+ }
+ case SRT_Mem: {
+ assert( nColumn==1 );
+ sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
+ sqlite3VdbeAddOp(v, OP_Goto, 0, end1);
+ break;
+ }
+ case SRT_Callback:
+ case SRT_Subroutine: {
+ int i;
+ sqlite3VdbeAddOp(v, OP_Integer, p->pEList->nExpr, 0);
+ sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
+ for(i=0; i<nColumn; i++){
+ sqlite3VdbeAddOp(v, OP_Column, -1-i, i);
+ }
+ if( eDest==SRT_Callback ){
+ sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
+ }else{
+ sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
+ }
+ sqlite3VdbeAddOp(v, OP_Pop, 2, 0);
+ break;
+ }
+ default: {
+ /* Do nothing */
+ break;
+ }
+ }
+ sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
+ sqlite3VdbeResolveLabel(v, end2);
+ sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
+ sqlite3VdbeResolveLabel(v, end1);
+ sqlite3VdbeAddOp(v, OP_SortReset, 0, 0);
+}
+
+/*
+** Return a pointer to a string containing the 'declaration type' of the
+** expression pExpr. The string may be treated as static by the caller.
+**
+** If the declaration type is the exact datatype definition extracted from
+** the original CREATE TABLE statement if the expression is a column.
+**
+** The declaration type for an expression is either TEXT, NUMERIC or ANY.
+** The declaration type for a ROWID field is INTEGER.
+*/
+static const char *columnType(Parse *pParse, SrcList *pTabList, Expr *pExpr){
+ char const *zType;
+ int j;
+ if( pExpr==0 || pTabList==0 ) return 0;
+
+ switch( pExpr->op ){
+ case TK_COLUMN: {
+ Table *pTab;
+ int iCol = pExpr->iColumn;
+ for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable; j++){}
+ assert( j<pTabList->nSrc );
+ pTab = pTabList->a[j].pTab;
+ if( iCol<0 ) iCol = pTab->iPKey;
+ assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+ if( iCol<0 ){
+ zType = "INTEGER";
+ }else{
+ zType = pTab->aCol[iCol].zType;
+ }
+ break;
+ }
+ case TK_AS:
+ zType = columnType(pParse, pTabList, pExpr->pLeft);
+ break;
+ case TK_SELECT: {
+ Select *pS = pExpr->pSelect;
+ zType = columnType(pParse, pS->pSrc, pS->pEList->a[0].pExpr);
+ break;
+ }
+ default:
+ zType = 0;
+ }
+
+ return zType;
+}
+
+/*
+** Generate code that will tell the VDBE the declaration types of columns
+** in the result set.
+*/
+static void generateColumnTypes(
+ Parse *pParse, /* Parser context */
+ SrcList *pTabList, /* List of tables */
+ ExprList *pEList /* Expressions defining the result set */
+){
+ Vdbe *v = pParse->pVdbe;
+ int i;
+ for(i=0; i<pEList->nExpr; i++){
+ Expr *p = pEList->a[i].pExpr;
+ const char *zType = columnType(pParse, pTabList, p);
+ if( zType==0 ) continue;
+ /* The vdbe must make it's own copy of the column-type, in case the
+ ** schema is reset before this virtual machine is deleted.
+ */
+ sqlite3VdbeSetColName(v, i+pEList->nExpr, zType, strlen(zType));
+ }
+}
+
+/*
+** Generate code that will tell the VDBE the names of columns
+** in the result set. This information is used to provide the
+** azCol[] values in the callback.
+*/
+static void generateColumnNames(
+ Parse *pParse, /* Parser context */
+ SrcList *pTabList, /* List of tables */
+ ExprList *pEList /* Expressions defining the result set */
+){
+ Vdbe *v = pParse->pVdbe;
+ int i, j;
+ sqlite3 *db = pParse->db;
+ int fullNames, shortNames;
+
+ /* If this is an EXPLAIN, skip this step */
+ if( pParse->explain ){
+ return;
+ }
+
+ assert( v!=0 );
+ if( pParse->colNamesSet || v==0 || sqlite3_malloc_failed ) return;
+ pParse->colNamesSet = 1;
+ fullNames = (db->flags & SQLITE_FullColNames)!=0;
+ shortNames = (db->flags & SQLITE_ShortColNames)!=0;
+ sqlite3VdbeSetNumCols(v, pEList->nExpr);
+ for(i=0; i<pEList->nExpr; i++){
+ Expr *p;
+ p = pEList->a[i].pExpr;
+ if( p==0 ) continue;
+ if( pEList->a[i].zName ){
+ char *zName = pEList->a[i].zName;
+ sqlite3VdbeSetColName(v, i, zName, strlen(zName));
+ continue;
+ }
+ if( p->op==TK_COLUMN && pTabList ){
+ Table *pTab;
+ char *zCol;
+ int iCol = p->iColumn;
+ for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
+ assert( j<pTabList->nSrc );
+ pTab = pTabList->a[j].pTab;
+ if( iCol<0 ) iCol = pTab->iPKey;
+ assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
+ if( iCol<0 ){
+ zCol = "_ROWID_";
+ }else{
+ zCol = pTab->aCol[iCol].zName;
+ }
+ if( !shortNames && !fullNames && p->span.z && p->span.z[0] ){
+ sqlite3VdbeSetColName(v, i, p->span.z, p->span.n);
+ }else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
+ char *zName = 0;
+ char *zTab;
+
+ zTab = pTabList->a[j].zAlias;
+ if( fullNames || zTab==0 ) zTab = pTab->zName;
+ sqlite3SetString(&zName, zTab, ".", zCol, 0);
+ sqlite3VdbeSetColName(v, i, zName, P3_DYNAMIC);
+ }else{
+ sqlite3VdbeSetColName(v, i, zCol, 0);
+ }
+ }else if( p->span.z && p->span.z[0] ){
+ sqlite3VdbeSetColName(v, i, p->span.z, p->span.n);
+ /* sqlite3VdbeCompressSpace(v, addr); */
+ }else{
+ char zName[30];
+ assert( p->op!=TK_COLUMN || pTabList==0 );
+ sprintf(zName, "column%d", i+1);
+ sqlite3VdbeSetColName(v, i, zName, 0);
+ }
+ }
+ generateColumnTypes(pParse, pTabList, pEList);
+}
+
+/*
+** Name of the connection operator, used for error messages.
+*/
+static const char *selectOpName(int id){
+ char *z;
+ switch( id ){
+ case TK_ALL: z = "UNION ALL"; break;
+ case TK_INTERSECT: z = "INTERSECT"; break;
+ case TK_EXCEPT: z = "EXCEPT"; break;
+ default: z = "UNION"; break;
+ }
+ return z;
+}
+
+/*
+** Forward declaration
+*/
+static int fillInColumnList(Parse*, Select*);
+
+/*
+** Given a SELECT statement, generate a Table structure that describes
+** the result set of that SELECT.
+*/
+Table *sqlite3ResultSetOfSelect(Parse *pParse, char *zTabName, Select *pSelect){
+ Table *pTab;
+ int i, j;
+ ExprList *pEList;
+ Column *aCol, *pCol;
+
+ if( fillInColumnList(pParse, pSelect) ){
+ return 0;
+ }
+ pTab = sqliteMalloc( sizeof(Table) );
+ if( pTab==0 ){
+ return 0;
+ }
+ pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
+ pEList = pSelect->pEList;
+ pTab->nCol = pEList->nExpr;
+ assert( pTab->nCol>0 );
+ pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
+ for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
+ Expr *pR;
+ char *zType;
+ char *zName;
+ Expr *p = pEList->a[i].pExpr;
+ assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
+ if( (zName = pEList->a[i].zName)!=0 ){
+ zName = sqliteStrDup(zName);
+ }else if( p->op==TK_DOT
+ && (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
+ int cnt;
+ zName = sqlite3MPrintf("%T", &pR->token);
+ for(j=cnt=0; j<i; j++){
+ if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
+ sqliteFree(zName);
+ zName = sqlite3MPrintf("%T_%d", &pR->token, ++cnt);
+ j = -1;
+ }
+ }
+ }else if( p->span.z && p->span.z[0] ){
+ zName = sqlite3MPrintf("%T", &p->span);
+ }else{
+ zName = sqlite3MPrintf("column%d", i+1);
+ }
+ sqlite3Dequote(zName);
+ pCol->zName = zName;
+
+ zType = sqliteStrDup(columnType(pParse, pSelect->pSrc ,p));
+ pCol->zType = zType;
+ pCol->affinity = SQLITE_AFF_NUMERIC;
+ if( zType ){
+ pCol->affinity = sqlite3AffinityType(zType, strlen(zType));
+ }
+ pCol->pColl = sqlite3ExprCollSeq(pParse, p);
+ if( !pCol->pColl ){
+ pCol->pColl = pParse->db->pDfltColl;
+ }
+ }
+ pTab->iPKey = -1;
+ return pTab;
+}
+
+/*
+** For the given SELECT statement, do three things.
+**
+** (1) Fill in the pTabList->a[].pTab fields in the SrcList that
+** defines the set of tables that should be scanned. For views,
+** fill pTabList->a[].pSelect with a copy of the SELECT statement
+** that implements the view. A copy is made of the view's SELECT
+** statement so that we can freely modify or delete that statement
+** without worrying about messing up the presistent representation
+** of the view.
+**
+** (2) Add terms to the WHERE clause to accomodate the NATURAL keyword
+** on joins and the ON and USING clause of joins.
+**
+** (3) Scan the list of columns in the result set (pEList) looking
+** for instances of the "*" operator or the TABLE.* operator.
+** If found, expand each "*" to be every column in every table
+** and TABLE.* to be every column in TABLE.
+**
+** Return 0 on success. If there are problems, leave an error message
+** in pParse and return non-zero.
+*/
+static int fillInColumnList(Parse *pParse, Select *p){
+ int i, j, k, rc;
+ SrcList *pTabList;
+ ExprList *pEList;
+ Table *pTab;
+ struct SrcList_item *pFrom;
+
+ if( p==0 || p->pSrc==0 ) return 1;
+ pTabList = p->pSrc;
+ pEList = p->pEList;
+
+ /* Look up every table in the table list.
+ */
+ for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+ if( pFrom->pTab ){
+ /* This routine has run before! No need to continue */
+ return 0;
+ }
+ if( pFrom->zName==0 ){
+ /* A sub-query in the FROM clause of a SELECT */
+ assert( pFrom->pSelect!=0 );
+ if( pFrom->zAlias==0 ){
+ pFrom->zAlias =
+ sqlite3MPrintf("sqlite_subquery_%p_", (void*)pFrom->pSelect);
+ }
+ pFrom->pTab = pTab =
+ sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
+ if( pTab==0 ){
+ return 1;
+ }
+ /* The isTransient flag indicates that the Table structure has been
+ ** dynamically allocated and may be freed at any time. In other words,
+ ** pTab is not pointing to a persistent table structure that defines
+ ** part of the schema. */
+ pTab->isTransient = 1;
+ }else{
+ /* An ordinary table or view name in the FROM clause */
+ pFrom->pTab = pTab =
+ sqlite3LocateTable(pParse,pFrom->zName,pFrom->zDatabase);
+ if( pTab==0 ){
+ return 1;
+ }
+ if( pTab->pSelect ){
+ /* We reach here if the named table is a really a view */
+ if( sqlite3ViewGetColumnNames(pParse, pTab) ){
+ return 1;
+ }
+ /* If pFrom->pSelect!=0 it means we are dealing with a
+ ** view within a view. The SELECT structure has already been
+ ** copied by the outer view so we can skip the copy step here
+ ** in the inner view.
+ */
+ if( pFrom->pSelect==0 ){
+ pFrom->pSelect = sqlite3SelectDup(pTab->pSelect);
+ }
+ }
+ }
+ }
+
+ /* Process NATURAL keywords, and ON and USING clauses of joins.
+ */
+ if( sqliteProcessJoin(pParse, p) ) return 1;
+
+ /* For every "*" that occurs in the column list, insert the names of
+ ** all columns in all tables. And for every TABLE.* insert the names
+ ** of all columns in TABLE. The parser inserted a special expression
+ ** with the TK_ALL operator for each "*" that it found in the column list.
+ ** The following code just has to locate the TK_ALL expressions and expand
+ ** each one to the list of all columns in all tables.
+ **
+ ** The first loop just checks to see if there are any "*" operators
+ ** that need expanding.
+ */
+ for(k=0; k<pEList->nExpr; k++){
+ Expr *pE = pEList->a[k].pExpr;
+ if( pE->op==TK_ALL ) break;
+ if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
+ && pE->pLeft && pE->pLeft->op==TK_ID ) break;
+ }
+ rc = 0;
+ if( k<pEList->nExpr ){
+ /*
+ ** If we get here it means the result set contains one or more "*"
+ ** operators that need to be expanded. Loop through each expression
+ ** in the result set and expand them one by one.
+ */
+ struct ExprList_item *a = pEList->a;
+ ExprList *pNew = 0;
+ for(k=0; k<pEList->nExpr; k++){
+ Expr *pE = a[k].pExpr;
+ if( pE->op!=TK_ALL &&
+ (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
+ /* This particular expression does not need to be expanded.
+ */
+ pNew = sqlite3ExprListAppend(pNew, a[k].pExpr, 0);
+ pNew->a[pNew->nExpr-1].zName = a[k].zName;
+ a[k].pExpr = 0;
+ a[k].zName = 0;
+ }else{
+ /* This expression is a "*" or a "TABLE.*" and needs to be
+ ** expanded. */
+ int tableSeen = 0; /* Set to 1 when TABLE matches */
+ char *zTName; /* text of name of TABLE */
+ if( pE->op==TK_DOT && pE->pLeft ){
+ zTName = sqlite3NameFromToken(&pE->pLeft->token);
+ }else{
+ zTName = 0;
+ }
+ for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
+ Table *pTab = pFrom->pTab;
+ char *zTabName = pFrom->zAlias;
+ if( zTabName==0 || zTabName[0]==0 ){
+ zTabName = pTab->zName;
+ }
+ if( zTName && (zTabName==0 || zTabName[0]==0 ||
+ sqlite3StrICmp(zTName, zTabName)!=0) ){
+ continue;
+ }
+ tableSeen = 1;
+ for(j=0; j<pTab->nCol; j++){
+ Expr *pExpr, *pLeft, *pRight;
+ char *zName = pTab->aCol[j].zName;
+
+ if( i>0 ){
+ struct SrcList_item *pLeft = &pTabList->a[i-1];
+ if( (pLeft->jointype & JT_NATURAL)!=0 &&
+ columnIndex(pLeft->pTab, zName)>=0 ){
+ /* In a NATURAL join, omit the join columns from the
+ ** table on the right */
+ continue;
+ }
+ if( sqlite3IdListIndex(pLeft->pUsing, zName)>=0 ){
+ /* In a join with a USING clause, omit columns in the
+ ** using clause from the table on the right. */
+ continue;
+ }
+ }
+ pRight = sqlite3Expr(TK_ID, 0, 0, 0);
+ if( pRight==0 ) break;
+ setToken(&pRight->token, zName);
+ if( zTabName && pTabList->nSrc>1 ){
+ pLeft = sqlite3Expr(TK_ID, 0, 0, 0);
+ pExpr = sqlite3Expr(TK_DOT, pLeft, pRight, 0);
+ if( pExpr==0 ) break;
+ setToken(&pLeft->token, zTabName);
+ setToken(&pExpr->span, sqlite3MPrintf("%s.%s", zTabName, zName));
+ pExpr->span.dyn = 1;
+ pExpr->token.z = 0;
+ pExpr->token.n = 0;
+ pExpr->token.dyn = 0;
+ }else{
+ pExpr = pRight;
+ pExpr->span = pExpr->token;
+ }
+ pNew = sqlite3ExprListAppend(pNew, pExpr, 0);
+ }
+ }
+ if( !tableSeen ){
+ if( zTName ){
+ sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
+ }else{
+ sqlite3ErrorMsg(pParse, "no tables specified");
+ }
+ rc = 1;
+ }
+ sqliteFree(zTName);
+ }
+ }
+ sqlite3ExprListDelete(pEList);
+ p->pEList = pNew;
+ }
+ return rc;
+}
+
+/*
+** This routine recursively unlinks the Select.pSrc.a[].pTab pointers
+** in a select structure. It just sets the pointers to NULL. This
+** routine is recursive in the sense that if the Select.pSrc.a[].pSelect
+** pointer is not NULL, this routine is called recursively on that pointer.
+**
+** This routine is called on the Select structure that defines a
+** VIEW in order to undo any bindings to tables. This is necessary
+** because those tables might be DROPed by a subsequent SQL command.
+** If the bindings are not removed, then the Select.pSrc->a[].pTab field
+** will be left pointing to a deallocated Table structure after the
+** DROP and a coredump will occur the next time the VIEW is used.
+*/
+void sqlite3SelectUnbind(Select *p){
+ int i;
+ SrcList *pSrc = p->pSrc;
+ struct SrcList_item *pItem;
+ Table *pTab;
+ if( p==0 ) return;
+ for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
+ if( (pTab = pItem->pTab)!=0 ){
+ if( pTab->isTransient ){
+ sqlite3DeleteTable(0, pTab);
+ }
+ pItem->pTab = 0;
+ if( pItem->pSelect ){
+ sqlite3SelectUnbind(pItem->pSelect);
+ }
+ }
+ }
+}
+
+/*
+** This routine associates entries in an ORDER BY expression list with
+** columns in a result. For each ORDER BY expression, the opcode of
+** the top-level node is changed to TK_COLUMN and the iColumn value of
+** the top-level node is filled in with column number and the iTable
+** value of the top-level node is filled with iTable parameter.
+**
+** If there are prior SELECT clauses, they are processed first. A match
+** in an earlier SELECT takes precedence over a later SELECT.
+**
+** Any entry that does not match is flagged as an error. The number
+** of errors is returned.
+*/
+static int matchOrderbyToColumn(
+ Parse *pParse, /* A place to leave error messages */
+ Select *pSelect, /* Match to result columns of this SELECT */
+ ExprList *pOrderBy, /* The ORDER BY values to match against columns */
+ int iTable, /* Insert this value in iTable */
+ int mustComplete /* If TRUE all ORDER BYs must match */
+){
+ int nErr = 0;
+ int i, j;
+ ExprList *pEList;
+
+ if( pSelect==0 || pOrderBy==0 ) return 1;
+ if( mustComplete ){
+ for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
+ }
+ if( fillInColumnList(pParse, pSelect) ){
+ return 1;
+ }
+ if( pSelect->pPrior ){
+ if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
+ return 1;
+ }
+ }
+ pEList = pSelect->pEList;
+ for(i=0; i<pOrderBy->nExpr; i++){
+ Expr *pE = pOrderBy->a[i].pExpr;
+ int iCol = -1;
+ if( pOrderBy->a[i].done ) continue;
+ if( sqlite3ExprIsInteger(pE, &iCol) ){
+ if( iCol<=0 || iCol>pEList->nExpr ){
+ sqlite3ErrorMsg(pParse,
+ "ORDER BY position %d should be between 1 and %d",
+ iCol, pEList->nExpr);
+ nErr++;
+ break;
+ }
+ if( !mustComplete ) continue;
+ iCol--;
+ }
+ for(j=0; iCol<0 && j<pEList->nExpr; j++){
+ if( pEList->a[j].zName && (pE->op==TK_ID || pE->op==TK_STRING) ){
+ char *zName, *zLabel;
+ zName = pEList->a[j].zName;
+ zLabel = sqlite3NameFromToken(&pE->token);
+ assert( zLabel!=0 );
+ if( sqlite3StrICmp(zName, zLabel)==0 ){
+ iCol = j;
+ }
+ sqliteFree(zLabel);
+ }
+ if( iCol<0 && sqlite3ExprCompare(pE, pEList->a[j].pExpr) ){
+ iCol = j;
+ }
+ }
+ if( iCol>=0 ){
+ pE->op = TK_COLUMN;
+ pE->iColumn = iCol;
+ pE->iTable = iTable;
+ pOrderBy->a[i].done = 1;
+ }
+ if( iCol<0 && mustComplete ){
+ sqlite3ErrorMsg(pParse,
+ "ORDER BY term number %d does not match any result column", i+1);
+ nErr++;
+ break;
+ }
+ }
+ return nErr;
+}
+
+/*
+** Get a VDBE for the given parser context. Create a new one if necessary.
+** If an error occurs, return NULL and leave a message in pParse.
+*/
+Vdbe *sqlite3GetVdbe(Parse *pParse){
+ Vdbe *v = pParse->pVdbe;
+ if( v==0 ){
+ v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
+ }
+ return v;
+}
+
+/*
+** Compute the iLimit and iOffset fields of the SELECT based on the
+** nLimit and nOffset fields. nLimit and nOffset hold the integers
+** that appear in the original SQL statement after the LIMIT and OFFSET
+** keywords. Or that hold -1 and 0 if those keywords are omitted.
+** iLimit and iOffset are the integer memory register numbers for
+** counters used to compute the limit and offset. If there is no
+** limit and/or offset, then iLimit and iOffset are negative.
+**
+** This routine changes the values if iLimit and iOffset only if
+** a limit or offset is defined by nLimit and nOffset. iLimit and
+** iOffset should have been preset to appropriate default values
+** (usually but not always -1) prior to calling this routine.
+** Only if nLimit>=0 or nOffset>0 do the limit registers get
+** redefined. The UNION ALL operator uses this property to force
+** the reuse of the same limit and offset registers across multiple
+** SELECT statements.
+*/
+static void computeLimitRegisters(Parse *pParse, Select *p){
+ /*
+ ** If the comparison is p->nLimit>0 then "LIMIT 0" shows
+ ** all rows. It is the same as no limit. If the comparision is
+ ** p->nLimit>=0 then "LIMIT 0" show no rows at all.
+ ** "LIMIT -1" always shows all rows. There is some
+ ** contraversy about what the correct behavior should be.
+ ** The current implementation interprets "LIMIT 0" to mean
+ ** no rows.
+ */
+ if( p->nLimit>=0 ){
+ int iMem = pParse->nMem++;
+ Vdbe *v = sqlite3GetVdbe(pParse);
+ if( v==0 ) return;
+ sqlite3VdbeAddOp(v, OP_Integer, -p->nLimit, 0);
+ sqlite3VdbeAddOp(v, OP_MemStore, iMem, 1);
+ VdbeComment((v, "# LIMIT counter"));
+ p->iLimit = iMem;
+ }
+ if( p->nOffset>0 ){
+ int iMem = pParse->nMem++;
+ Vdbe *v = sqlite3GetVdbe(pParse);
+ if( v==0 ) return;
+ sqlite3VdbeAddOp(v, OP_Integer, -p->nOffset, 0);
+ sqlite3VdbeAddOp(v, OP_MemStore, iMem, 1);
+ VdbeComment((v, "# OFFSET counter"));
+ p->iOffset = iMem;
+ }
+}
+
+/*
+** Generate VDBE instructions that will open a transient table that
+** will be used for an index or to store keyed results for a compound
+** select. In other words, open a transient table that needs a
+** KeyInfo structure. The number of columns in the KeyInfo is determined
+** by the result set of the SELECT statement in the second argument.
+**
+** Specifically, this routine is called to open an index table for
+** DISTINCT, UNION, INTERSECT and EXCEPT select statements (but not
+** UNION ALL).
+**
+** Make the new table a KeyAsData table if keyAsData is true.
+**
+** The value returned is the address of the OP_OpenTemp instruction.
+*/
+static int openTempIndex(Parse *pParse, Select *p, int iTab, int keyAsData){
+ KeyInfo *pKeyInfo;
+ int nColumn;
+ sqlite3 *db = pParse->db;
+ int i;
+ Vdbe *v = pParse->pVdbe;
+ int addr;
+
+ if( fillInColumnList(pParse, p) ){
+ return 0;
+ }
+ nColumn = p->pEList->nExpr;
+ pKeyInfo = sqliteMalloc( sizeof(*pKeyInfo)+nColumn*sizeof(CollSeq*) );
+ if( pKeyInfo==0 ) return 0;
+ pKeyInfo->enc = db->enc;
+ pKeyInfo->nField = nColumn;
+ for(i=0; i<nColumn; i++){
+ pKeyInfo->aColl[i] = sqlite3ExprCollSeq(pParse, p->pEList->a[i].pExpr);
+ if( !pKeyInfo->aColl[i] ){
+ pKeyInfo->aColl[i] = db->pDfltColl;
+ }
+ }
+ addr = sqlite3VdbeOp3(v, OP_OpenTemp, iTab, 0,
+ (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
+ if( keyAsData ){
+ sqlite3VdbeAddOp(v, OP_KeyAsData, iTab, 1);
+ }
+ return addr;
+}
+
+/*
+** Add the address "addr" to the set of all OpenTemp opcode addresses
+** that are being accumulated in p->ppOpenTemp.
+*/
+static int multiSelectOpenTempAddr(Select *p, int addr){
+ IdList *pList = *p->ppOpenTemp = sqlite3IdListAppend(*p->ppOpenTemp, 0);
+ if( pList==0 ){
+ return SQLITE_NOMEM;
+ }
+ pList->a[pList->nId-1].idx = addr;
+ return SQLITE_OK;
+}
+
+/*
+** Return the appropriate collating sequence for the iCol-th column of
+** the result set for the compound-select statement "p". Return NULL if
+** the column has no default collating sequence.
+**
+** The collating sequence for the compound select is taken from the
+** left-most term of the select that has a collating sequence.
+*/
+static CollSeq *multiSelectCollSeq(Parse *pParse, Select *p, int iCol){
+ CollSeq *pRet;
+ if( p->pPrior ){
+ pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
+ }else{
+ pRet = 0;
+ }
+ if( pRet==0 ){
+ pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
+ }
+ return pRet;
+}
+
+/*
+** This routine is called to process a query that is really the union
+** or intersection of two or more separate queries.
+**
+** "p" points to the right-most of the two queries. the query on the
+** left is p->pPrior. The left query could also be a compound query
+** in which case this routine will be called recursively.
+**
+** The results of the total query are to be written into a destination
+** of type eDest with parameter iParm.
+**
+** Example 1: Consider a three-way compound SQL statement.
+**
+** SELECT a FROM t1 UNION SELECT b FROM t2 UNION SELECT c FROM t3
+**
+** This statement is parsed up as follows:
+**
+** SELECT c FROM t3
+** |
+** `-----> SELECT b FROM t2
+** |
+** `------> SELECT a FROM t1
+**
+** The arrows in the diagram above represent the Select.pPrior pointer.
+** So if this routine is called with p equal to the t3 query, then
+** pPrior will be the t2 query. p->op will be TK_UNION in this case.
+**
+** Notice that because of the way SQLite parses compound SELECTs, the
+** individual selects always group from left to right.
+*/
+static int multiSelect(
+ Parse *pParse, /* Parsing context */
+ Select *p, /* The right-most of SELECTs to be coded */
+ int eDest, /* \___ Store query results as specified */
+ int iParm, /* / by these two parameters. */
+ char *aff /* If eDest is SRT_Union, the affinity string */
+){
+ int rc = SQLITE_OK; /* Success code from a subroutine */
+ Select *pPrior; /* Another SELECT immediately to our left */
+ Vdbe *v; /* Generate code to this VDBE */
+ IdList *pOpenTemp = 0;/* OP_OpenTemp opcodes that need a KeyInfo */
+ int aAddr[5]; /* Addresses of SetNumColumns operators */
+ int nAddr = 0; /* Number used */
+ int nCol; /* Number of columns in the result set */
+
+ /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs. Only
+ ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
+ */
+ if( p==0 || p->pPrior==0 ){
+ rc = 1;
+ goto multi_select_end;
+ }
+ pPrior = p->pPrior;
+ if( pPrior->pOrderBy ){
+ sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
+ selectOpName(p->op));
+ rc = 1;
+ goto multi_select_end;
+ }
+ if( pPrior->nLimit>=0 || pPrior->nOffset>0 ){
+ sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
+ selectOpName(p->op));
+ rc = 1;
+ goto multi_select_end;
+ }
+
+ /* Make sure we have a valid query engine. If not, create a new one.
+ */
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ){
+ rc = 1;
+ goto multi_select_end;
+ }
+
+ /* If *p this is the right-most select statement, then initialize
+ ** p->ppOpenTemp to point to pOpenTemp. If *p is not the right most
+ ** statement then p->ppOpenTemp will have already been initialized
+ ** by a prior call to this same procedure. Pass along the pOpenTemp
+ ** pointer to pPrior, the next statement to our left.
+ */
+ if( p->ppOpenTemp==0 ){
+ p->ppOpenTemp = &pOpenTemp;
+ }
+ pPrior->ppOpenTemp = p->ppOpenTemp;
+
+ /* Create the destination temporary table if necessary
+ */
+ if( eDest==SRT_TempTable ){
+ assert( p->pEList );
+ sqlite3VdbeAddOp(v, OP_OpenTemp, iParm, 0);
+ assert( nAddr==0 );
+ aAddr[nAddr++] = sqlite3VdbeAddOp(v, OP_SetNumColumns, iParm, 0);
+ eDest = SRT_Table;
+ }
+
+ /* Generate code for the left and right SELECT statements.
+ */
+ switch( p->op ){
+ case TK_ALL: {
+ if( p->pOrderBy==0 ){
+ pPrior->nLimit = p->nLimit;
+ pPrior->nOffset = p->nOffset;
+ rc = sqlite3Select(pParse, pPrior, eDest, iParm, 0, 0, 0, aff);
+ if( rc ){
+ goto multi_select_end;
+ }
+ p->pPrior = 0;
+ p->iLimit = pPrior->iLimit;
+ p->iOffset = pPrior->iOffset;
+ p->nLimit = -1;
+ p->nOffset = 0;
+ rc = sqlite3Select(pParse, p, eDest, iParm, 0, 0, 0, aff);
+ p->pPrior = pPrior;
+ if( rc ){
+ goto multi_select_end;
+ }
+ break;
+ }
+ /* For UNION ALL ... ORDER BY fall through to the next case */
+ }
+ case TK_EXCEPT:
+ case TK_UNION: {
+ int unionTab; /* Cursor number of the temporary table holding result */
+ int op = 0; /* One of the SRT_ operations to apply to self */
+ int priorOp; /* The SRT_ operation to apply to prior selects */
+ int nLimit, nOffset; /* Saved values of p->nLimit and p->nOffset */
+ ExprList *pOrderBy; /* The ORDER BY clause for the right SELECT */
+ int addr;
+
+ priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
+ if( eDest==priorOp && p->pOrderBy==0 && p->nLimit<0 && p->nOffset==0 ){
+ /* We can reuse a temporary table generated by a SELECT to our
+ ** right.
+ */
+ unionTab = iParm;
+ }else{
+ /* We will need to create our own temporary table to hold the
+ ** intermediate results.
+ */
+ unionTab = pParse->nTab++;
+ if( p->pOrderBy
+ && matchOrderbyToColumn(pParse, p, p->pOrderBy, unionTab, 1) ){
+ rc = 1;
+ goto multi_select_end;
+ }
+ addr = sqlite3VdbeAddOp(v, OP_OpenTemp, unionTab, 0);
+ if( p->op!=TK_ALL ){
+ rc = multiSelectOpenTempAddr(p, addr);
+ if( rc!=SQLITE_OK ){
+ goto multi_select_end;
+ }
+ sqlite3VdbeAddOp(v, OP_KeyAsData, unionTab, 1);
+ }
+ assert( nAddr<sizeof(aAddr)/sizeof(aAddr[0]) );
+ aAddr[nAddr++] = sqlite3VdbeAddOp(v, OP_SetNumColumns, unionTab, 0);
+ assert( p->pEList );
+ }
+
+ /* Code the SELECT statements to our left
+ */
+ rc = sqlite3Select(pParse, pPrior, priorOp, unionTab, 0, 0, 0, aff);
+ if( rc ){
+ goto multi_select_end;
+ }
+
+ /* Code the current SELECT statement
+ */
+ switch( p->op ){
+ case TK_EXCEPT: op = SRT_Except; break;
+ case TK_UNION: op = SRT_Union; break;
+ case TK_ALL: op = SRT_Table; break;
+ }
+ p->pPrior = 0;
+ pOrderBy = p->pOrderBy;
+ p->pOrderBy = 0;
+ nLimit = p->nLimit;
+ p->nLimit = -1;
+ nOffset = p->nOffset;
+ p->nOffset = 0;
+ rc = sqlite3Select(pParse, p, op, unionTab, 0, 0, 0, aff);
+ p->pPrior = pPrior;
+ p->pOrderBy = pOrderBy;
+ p->nLimit = nLimit;
+ p->nOffset = nOffset;
+ if( rc ){
+ goto multi_select_end;
+ }
+
+
+ /* Convert the data in the temporary table into whatever form
+ ** it is that we currently need.
+ */
+ if( eDest!=priorOp || unionTab!=iParm ){
+ int iCont, iBreak, iStart;
+ assert( p->pEList );
+ if( eDest==SRT_Callback ){
+ generateColumnNames(pParse, 0, p->pEList);
+ }
+ iBreak = sqlite3VdbeMakeLabel(v);
+ iCont = sqlite3VdbeMakeLabel(v);
+ sqlite3VdbeAddOp(v, OP_Rewind, unionTab, iBreak);
+ computeLimitRegisters(pParse, p);
+ iStart = sqlite3VdbeCurrentAddr(v);
+ rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
+ p->pOrderBy, -1, eDest, iParm,
+ iCont, iBreak, 0);
+ if( rc ){
+ rc = 1;
+ goto multi_select_end;
+ }
+ sqlite3VdbeResolveLabel(v, iCont);
+ sqlite3VdbeAddOp(v, OP_Next, unionTab, iStart);
+ sqlite3VdbeResolveLabel(v, iBreak);
+ sqlite3VdbeAddOp(v, OP_Close, unionTab, 0);
+ }
+ break;
+ }
+ case TK_INTERSECT: {
+ int tab1, tab2;
+ int iCont, iBreak, iStart;
+ int nLimit, nOffset;
+ int addr;
+
+ /* INTERSECT is different from the others since it requires
+ ** two temporary tables. Hence it has its own case. Begin
+ ** by allocating the tables we will need.
+ */
+ tab1 = pParse->nTab++;
+ tab2 = pParse->nTab++;
+ if( p->pOrderBy && matchOrderbyToColumn(pParse,p,p->pOrderBy,tab1,1) ){
+ rc = 1;
+ goto multi_select_end;
+ }
+
+ addr = sqlite3VdbeAddOp(v, OP_OpenTemp, tab1, 0);
+ rc = multiSelectOpenTempAddr(p, addr);
+ if( rc!=SQLITE_OK ){
+ goto multi_select_end;
+ }
+ sqlite3VdbeAddOp(v, OP_KeyAsData, tab1, 1);
+ assert( nAddr<sizeof(aAddr)/sizeof(aAddr[0]) );
+ aAddr[nAddr++] = sqlite3VdbeAddOp(v, OP_SetNumColumns, tab1, 0);
+ assert( p->pEList );
+
+ /* Code the SELECTs to our left into temporary table "tab1".
+ */
+ rc = sqlite3Select(pParse, pPrior, SRT_Union, tab1, 0, 0, 0, aff);
+ if( rc ){
+ goto multi_select_end;
+ }
+
+ /* Code the current SELECT into temporary table "tab2"
+ */
+ addr = sqlite3VdbeAddOp(v, OP_OpenTemp, tab2, 0);
+ rc = multiSelectOpenTempAddr(p, addr);
+ if( rc!=SQLITE_OK ){
+ goto multi_select_end;
+ }
+ sqlite3VdbeAddOp(v, OP_KeyAsData, tab2, 1);
+ assert( nAddr<sizeof(aAddr)/sizeof(aAddr[0]) );
+ aAddr[nAddr++] = sqlite3VdbeAddOp(v, OP_SetNumColumns, tab2, 0);
+ p->pPrior = 0;
+ nLimit = p->nLimit;
+ p->nLimit = -1;
+ nOffset = p->nOffset;
+ p->nOffset = 0;
+ rc = sqlite3Select(pParse, p, SRT_Union, tab2, 0, 0, 0, aff);
+ p->pPrior = pPrior;
+ p->nLimit = nLimit;
+ p->nOffset = nOffset;
+ if( rc ){
+ goto multi_select_end;
+ }
+
+ /* Generate code to take the intersection of the two temporary
+ ** tables.
+ */
+ assert( p->pEList );
+ if( eDest==SRT_Callback ){
+ generateColumnNames(pParse, 0, p->pEList);
+ }
+ iBreak = sqlite3VdbeMakeLabel(v);
+ iCont = sqlite3VdbeMakeLabel(v);
+ sqlite3VdbeAddOp(v, OP_Rewind, tab1, iBreak);
+ computeLimitRegisters(pParse, p);
+ iStart = sqlite3VdbeAddOp(v, OP_FullKey, tab1, 0);
+ sqlite3VdbeAddOp(v, OP_NotFound, tab2, iCont);
+ rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
+ p->pOrderBy, -1, eDest, iParm,
+ iCont, iBreak, 0);
+ if( rc ){
+ rc = 1;
+ goto multi_select_end;
+ }
+ sqlite3VdbeResolveLabel(v, iCont);
+ sqlite3VdbeAddOp(v, OP_Next, tab1, iStart);
+ sqlite3VdbeResolveLabel(v, iBreak);
+ sqlite3VdbeAddOp(v, OP_Close, tab2, 0);
+ sqlite3VdbeAddOp(v, OP_Close, tab1, 0);
+ break;
+ }
+ }
+
+ /* Make sure all SELECTs in the statement have the same number of elements
+ ** in their result sets.
+ */
+ assert( p->pEList && pPrior->pEList );
+ if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
+ sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
+ " do not have the same number of result columns", selectOpName(p->op));
+ rc = 1;
+ goto multi_select_end;
+ }
+
+ /* Set the number of columns in temporary tables
+ */
+ nCol = p->pEList->nExpr;
+ while( nAddr>0 ){
+ nAddr--;
+ sqlite3VdbeChangeP2(v, aAddr[nAddr], nCol);
+ }
+
+ /* Compute collating sequences used by either the ORDER BY clause or
+ ** by any temporary tables needed to implement the compound select.
+ ** Attach the KeyInfo structure to all temporary tables. Invoke the
+ ** ORDER BY processing if there is an ORDER BY clause.
+ **
+ ** This section is run by the right-most SELECT statement only.
+ ** SELECT statements to the left always skip this part. The right-most
+ ** SELECT might also skip this part if it has no ORDER BY clause and
+ ** no temp tables are required.
+ */
+ if( p->pOrderBy || (pOpenTemp && pOpenTemp->nId>0) ){
+ int i; /* Loop counter */
+ KeyInfo *pKeyInfo; /* Collating sequence for the result set */
+
+ assert( p->ppOpenTemp == &pOpenTemp );
+ pKeyInfo = sqliteMalloc(sizeof(*pKeyInfo)+nCol*sizeof(CollSeq*));
+ if( !pKeyInfo ){
+ rc = SQLITE_NOMEM;
+ goto multi_select_end;
+ }
+
+ pKeyInfo->enc = pParse->db->enc;
+ pKeyInfo->nField = nCol;
+
+ for(i=0; i<nCol; i++){
+ pKeyInfo->aColl[i] = multiSelectCollSeq(pParse, p, i);
+ if( !pKeyInfo->aColl[i] ){
+ pKeyInfo->aColl[i] = pParse->db->pDfltColl;
+ }
+ }
+
+ for(i=0; pOpenTemp && i<pOpenTemp->nId; i++){
+ int p3type = (i==0?P3_KEYINFO_HANDOFF:P3_KEYINFO);
+ int addr = pOpenTemp->a[i].idx;
+ sqlite3VdbeChangeP3(v, addr, (char *)pKeyInfo, p3type);
+ }
+
+ if( p->pOrderBy ){
+ struct ExprList_item *pOrderByTerm = p->pOrderBy->a;
+ for(i=0; i<p->pOrderBy->nExpr; i++, pOrderByTerm++){
+ Expr *pExpr = pOrderByTerm->pExpr;
+ char *zName = pOrderByTerm->zName;
+ assert( pExpr->op==TK_COLUMN && pExpr->iColumn<nCol );
+ assert( !pExpr->pColl );
+ if( zName ){
+ pExpr->pColl = sqlite3LocateCollSeq(pParse, zName, -1);
+ }else{
+ pExpr->pColl = pKeyInfo->aColl[pExpr->iColumn];
+ }
+ }
+ generateSortTail(pParse, p, v, p->pEList->nExpr, eDest, iParm);
+ }
+
+ if( !pOpenTemp ){
+ /* This happens for UNION ALL ... ORDER BY */
+ sqliteFree(pKeyInfo);
+ }
+ }
+
+multi_select_end:
+ if( pOpenTemp ){
+ sqlite3IdListDelete(pOpenTemp);
+ }
+ p->ppOpenTemp = 0;
+ return rc;
+}
+
+/*
+** Scan through the expression pExpr. Replace every reference to
+** a column in table number iTable with a copy of the iColumn-th
+** entry in pEList. (But leave references to the ROWID column
+** unchanged.)
+**
+** This routine is part of the flattening procedure. A subquery
+** whose result set is defined by pEList appears as entry in the
+** FROM clause of a SELECT such that the VDBE cursor assigned to that
+** FORM clause entry is iTable. This routine make the necessary
+** changes to pExpr so that it refers directly to the source table
+** of the subquery rather the result set of the subquery.
+*/
+static void substExprList(ExprList*,int,ExprList*); /* Forward Decl */
+static void substExpr(Expr *pExpr, int iTable, ExprList *pEList){
+ if( pExpr==0 ) return;
+ if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
+ if( pExpr->iColumn<0 ){
+ pExpr->op = TK_NULL;
+ }else{
+ Expr *pNew;
+ assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
+ assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
+ pNew = pEList->a[pExpr->iColumn].pExpr;
+ assert( pNew!=0 );
+ pExpr->op = pNew->op;
+ assert( pExpr->pLeft==0 );
+ pExpr->pLeft = sqlite3ExprDup(pNew->pLeft);
+ assert( pExpr->pRight==0 );
+ pExpr->pRight = sqlite3ExprDup(pNew->pRight);
+ assert( pExpr->pList==0 );
+ pExpr->pList = sqlite3ExprListDup(pNew->pList);
+ pExpr->iTable = pNew->iTable;
+ pExpr->iColumn = pNew->iColumn;
+ pExpr->iAgg = pNew->iAgg;
+ sqlite3TokenCopy(&pExpr->token, &pNew->token);
+ sqlite3TokenCopy(&pExpr->span, &pNew->span);
+ }
+ }else{
+ substExpr(pExpr->pLeft, iTable, pEList);
+ substExpr(pExpr->pRight, iTable, pEList);
+ substExprList(pExpr->pList, iTable, pEList);
+ }
+}
+static void
+substExprList(ExprList *pList, int iTable, ExprList *pEList){
+ int i;
+ if( pList==0 ) return;
+ for(i=0; i<pList->nExpr; i++){
+ substExpr(pList->a[i].pExpr, iTable, pEList);
+ }
+}
+
+/*
+** This routine attempts to flatten subqueries in order to speed
+** execution. It returns 1 if it makes changes and 0 if no flattening
+** occurs.
+**
+** To understand the concept of flattening, consider the following
+** query:
+**
+** SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
+**
+** The default way of implementing this query is to execute the
+** subquery first and store the results in a temporary table, then
+** run the outer query on that temporary table. This requires two
+** passes over the data. Furthermore, because the temporary table
+** has no indices, the WHERE clause on the outer query cannot be
+** optimized.
+**
+** This routine attempts to rewrite queries such as the above into
+** a single flat select, like this:
+**
+** SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
+**
+** The code generated for this simpification gives the same result
+** but only has to scan the data once. And because indices might
+** exist on the table t1, a complete scan of the data might be
+** avoided.
+**
+** Flattening is only attempted if all of the following are true:
+**
+** (1) The subquery and the outer query do not both use aggregates.
+**
+** (2) The subquery is not an aggregate or the outer query is not a join.
+**
+** (3) The subquery is not the right operand of a left outer join, or
+** the subquery is not itself a join. (Ticket #306)
+**
+** (4) The subquery is not DISTINCT or the outer query is not a join.
+**
+** (5) The subquery is not DISTINCT or the outer query does not use
+** aggregates.
+**
+** (6) The subquery does not use aggregates or the outer query is not
+** DISTINCT.
+**
+** (7) The subquery has a FROM clause.
+**
+** (8) The subquery does not use LIMIT or the outer query is not a join.
+**
+** (9) The subquery does not use LIMIT or the outer query does not use
+** aggregates.
+**
+** (10) The subquery does not use aggregates or the outer query does not
+** use LIMIT.
+**
+** (11) The subquery and the outer query do not both have ORDER BY clauses.
+**
+** (12) The subquery is not the right term of a LEFT OUTER JOIN or the
+** subquery has no WHERE clause. (added by ticket #350)
+**
+** In this routine, the "p" parameter is a pointer to the outer query.
+** The subquery is p->pSrc->a[iFrom]. isAgg is true if the outer query
+** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
+**
+** If flattening is not attempted, this routine is a no-op and returns 0.
+** If flattening is attempted this routine returns 1.
+**
+** All of the expression analysis must occur on both the outer query and
+** the subquery before this routine runs.
+*/
+static int flattenSubquery(
+ Parse *pParse, /* The parsing context */
+ Select *p, /* The parent or outer SELECT statement */
+ int iFrom, /* Index in p->pSrc->a[] of the inner subquery */
+ int isAgg, /* True if outer SELECT uses aggregate functions */
+ int subqueryIsAgg /* True if the subquery uses aggregate functions */
+){
+ Select *pSub; /* The inner query or "subquery" */
+ SrcList *pSrc; /* The FROM clause of the outer query */
+ SrcList *pSubSrc; /* The FROM clause of the subquery */
+ ExprList *pList; /* The result set of the outer query */
+ int iParent; /* VDBE cursor number of the pSub result set temp table */
+ int i; /* Loop counter */
+ Expr *pWhere; /* The WHERE clause */
+ struct SrcList_item *pSubitem; /* The subquery */
+
+ /* Check to see if flattening is permitted. Return 0 if not.
+ */
+ if( p==0 ) return 0;
+ pSrc = p->pSrc;
+ assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
+ pSubitem = &pSrc->a[iFrom];
+ pSub = pSubitem->pSelect;
+ assert( pSub!=0 );
+ if( isAgg && subqueryIsAgg ) return 0;
+ if( subqueryIsAgg && pSrc->nSrc>1 ) return 0;
+ pSubSrc = pSub->pSrc;
+ assert( pSubSrc );
+ if( pSubSrc->nSrc==0 ) return 0;
+ if( (pSub->isDistinct || pSub->nLimit>=0) && (pSrc->nSrc>1 || isAgg) ){
+ return 0;
+ }
+ if( (p->isDistinct || p->nLimit>=0) && subqueryIsAgg ) return 0;
+ if( p->pOrderBy && pSub->pOrderBy ) return 0;
+
+ /* Restriction 3: If the subquery is a join, make sure the subquery is
+ ** not used as the right operand of an outer join. Examples of why this
+ ** is not allowed:
+ **
+ ** t1 LEFT OUTER JOIN (t2 JOIN t3)
+ **
+ ** If we flatten the above, we would get
+ **
+ ** (t1 LEFT OUTER JOIN t2) JOIN t3
+ **
+ ** which is not at all the same thing.
+ */
+ if( pSubSrc->nSrc>1 && iFrom>0 && (pSrc->a[iFrom-1].jointype & JT_OUTER)!=0 ){
+ return 0;
+ }
+
+ /* Restriction 12: If the subquery is the right operand of a left outer
+ ** join, make sure the subquery has no WHERE clause.
+ ** An examples of why this is not allowed:
+ **
+ ** t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
+ **
+ ** If we flatten the above, we would get
+ **
+ ** (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
+ **
+ ** But the t2.x>0 test will always fail on a NULL row of t2, which
+ ** effectively converts the OUTER JOIN into an INNER JOIN.
+ */
+ if( iFrom>0 && (pSrc->a[iFrom-1].jointype & JT_OUTER)!=0
+ && pSub->pWhere!=0 ){
+ return 0;
+ }
+
+ /* If we reach this point, it means flattening is permitted for the
+ ** iFrom-th entry of the FROM clause in the outer query.
+ */
+
+ /* Move all of the FROM elements of the subquery into the
+ ** the FROM clause of the outer query. Before doing this, remember
+ ** the cursor number for the original outer query FROM element in
+ ** iParent. The iParent cursor will never be used. Subsequent code
+ ** will scan expressions looking for iParent references and replace
+ ** those references with expressions that resolve to the subquery FROM
+ ** elements we are now copying in.
+ */
+ iParent = pSubitem->iCursor;
+ {
+ int nSubSrc = pSubSrc->nSrc;
+ int jointype = pSubitem->jointype;
+ Table *pTab = pSubitem->pTab;
+
+ if( pTab && pTab->isTransient ){
+ sqlite3DeleteTable(0, pSubitem->pTab);
+ }
+ sqliteFree(pSubitem->zDatabase);
+ sqliteFree(pSubitem->zName);
+ sqliteFree(pSubitem->zAlias);
+ if( nSubSrc>1 ){
+ int extra = nSubSrc - 1;
+ for(i=1; i<nSubSrc; i++){
+ pSrc = sqlite3SrcListAppend(pSrc, 0, 0);
+ }
+ p->pSrc = pSrc;
+ for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
+ pSrc->a[i] = pSrc->a[i-extra];
+ }
+ }
+ for(i=0; i<nSubSrc; i++){
+ pSrc->a[i+iFrom] = pSubSrc->a[i];
+ memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
+ }
+ pSrc->a[iFrom+nSubSrc-1].jointype = jointype;
+ }
+
+ /* Now begin substituting subquery result set expressions for
+ ** references to the iParent in the outer query.
+ **
+ ** Example:
+ **
+ ** SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
+ ** \ \_____________ subquery __________/ /
+ ** \_____________________ outer query ______________________________/
+ **
+ ** We look at every expression in the outer query and every place we see
+ ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
+ */
+ substExprList(p->pEList, iParent, pSub->pEList);
+ pList = p->pEList;
+ for(i=0; i<pList->nExpr; i++){
+ Expr *pExpr;
+ if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
+ pList->a[i].zName = sqliteStrNDup(pExpr->span.z, pExpr->span.n);
+ }
+ }
+ if( isAgg ){
+ substExprList(p->pGroupBy, iParent, pSub->pEList);
+ substExpr(p->pHaving, iParent, pSub->pEList);
+ }
+ if( pSub->pOrderBy ){
+ assert( p->pOrderBy==0 );
+ p->pOrderBy = pSub->pOrderBy;
+ pSub->pOrderBy = 0;
+ }else if( p->pOrderBy ){
+ substExprList(p->pOrderBy, iParent, pSub->pEList);
+ }
+ if( pSub->pWhere ){
+ pWhere = sqlite3ExprDup(pSub->pWhere);
+ }else{
+ pWhere = 0;
+ }
+ if( subqueryIsAgg ){
+ assert( p->pHaving==0 );
+ p->pHaving = p->pWhere;
+ p->pWhere = pWhere;
+ substExpr(p->pHaving, iParent, pSub->pEList);
+ p->pHaving = sqlite3ExprAnd(p->pHaving, sqlite3ExprDup(pSub->pHaving));
+ assert( p->pGroupBy==0 );
+ p->pGroupBy = sqlite3ExprListDup(pSub->pGroupBy);
+ }else{
+ substExpr(p->pWhere, iParent, pSub->pEList);
+ p->pWhere = sqlite3ExprAnd(p->pWhere, pWhere);
+ }
+
+ /* The flattened query is distinct if either the inner or the
+ ** outer query is distinct.
+ */
+ p->isDistinct = p->isDistinct || pSub->isDistinct;
+
+ /* Transfer the limit expression from the subquery to the outer
+ ** query.
+ */
+ if( pSub->nLimit>=0 ){
+ if( p->nLimit<0 ){
+ p->nLimit = pSub->nLimit;
+ }else if( p->nLimit+p->nOffset > pSub->nLimit+pSub->nOffset ){
+ p->nLimit = pSub->nLimit + pSub->nOffset - p->nOffset;
+ }
+ }
+ p->nOffset += pSub->nOffset;
+
+ /* Finially, delete what is left of the subquery and return
+ ** success.
+ */
+ sqlite3SelectDelete(pSub);
+ return 1;
+}
+
+/*
+** Analyze the SELECT statement passed in as an argument to see if it
+** is a simple min() or max() query. If it is and this query can be
+** satisfied using a single seek to the beginning or end of an index,
+** then generate the code for this SELECT and return 1. If this is not a
+** simple min() or max() query, then return 0;
+**
+** A simply min() or max() query looks like this:
+**
+** SELECT min(a) FROM table;
+** SELECT max(a) FROM table;
+**
+** The query may have only a single table in its FROM argument. There
+** can be no GROUP BY or HAVING or WHERE clauses. The result set must
+** be the min() or max() of a single column of the table. The column
+** in the min() or max() function must be indexed.
+**
+** The parameters to this routine are the same as for sqlite3Select().
+** See the header comment on that routine for additional information.
+*/
+static int simpleMinMaxQuery(Parse *pParse, Select *p, int eDest, int iParm){
+ Expr *pExpr;
+ int iCol;
+ Table *pTab;
+ Index *pIdx;
+ int base;
+ Vdbe *v;
+ int seekOp;
+ int cont;
+ ExprList *pEList, *pList, eList;
+ struct ExprList_item eListItem;
+ SrcList *pSrc;
+
+
+ /* Check to see if this query is a simple min() or max() query. Return
+ ** zero if it is not.
+ */
+ if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
+ pSrc = p->pSrc;
+ if( pSrc->nSrc!=1 ) return 0;
+ pEList = p->pEList;
+ if( pEList->nExpr!=1 ) return 0;
+ pExpr = pEList->a[0].pExpr;
+ if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
+ pList = pExpr->pList;
+ if( pList==0 || pList->nExpr!=1 ) return 0;
+ if( pExpr->token.n!=3 ) return 0;
+ if( sqlite3StrNICmp(pExpr->token.z,"min",3)==0 ){
+ seekOp = OP_Rewind;
+ }else if( sqlite3StrNICmp(pExpr->token.z,"max",3)==0 ){
+ seekOp = OP_Last;
+ }else{
+ return 0;
+ }
+ pExpr = pList->a[0].pExpr;
+ if( pExpr->op!=TK_COLUMN ) return 0;
+ iCol = pExpr->iColumn;
+ pTab = pSrc->a[0].pTab;
+
+ /* If we get to here, it means the query is of the correct form.
+ ** Check to make sure we have an index and make pIdx point to the
+ ** appropriate index. If the min() or max() is on an INTEGER PRIMARY
+ ** key column, no index is necessary so set pIdx to NULL. If no
+ ** usable index is found, return 0.
+ */
+ if( iCol<0 ){
+ pIdx = 0;
+ }else{
+ CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
+ for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
+ assert( pIdx->nColumn>=1 );
+ if( pIdx->aiColumn[0]==iCol && pIdx->keyInfo.aColl[0]==pColl ) break;
+ }
+ if( pIdx==0 ) return 0;
+ }
+
+ /* Identify column types if we will be using the callback. This
+ ** step is skipped if the output is going to a table or a memory cell.
+ ** The column names have already been generated in the calling function.
+ */
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ) return 0;
+
+ /* If the output is destined for a temporary table, open that table.
+ */
+ if( eDest==SRT_TempTable ){
+ sqlite3VdbeAddOp(v, OP_OpenTemp, iParm, 0);
+ sqlite3VdbeAddOp(v, OP_SetNumColumns, iParm, 1);
+ }
+
+ /* Generating code to find the min or the max. Basically all we have
+ ** to do is find the first or the last entry in the chosen index. If
+ ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
+ ** or last entry in the main table.
+ */
+ sqlite3CodeVerifySchema(pParse, pTab->iDb);
+ base = pSrc->a[0].iCursor;
+ computeLimitRegisters(pParse, p);
+ if( pSrc->a[0].pSelect==0 ){
+ sqlite3OpenTableForReading(v, base, pTab);
+ }
+ cont = sqlite3VdbeMakeLabel(v);
+ if( pIdx==0 ){
+ sqlite3VdbeAddOp(v, seekOp, base, 0);
+ }else{
+ sqlite3VdbeAddOp(v, OP_Integer, pIdx->iDb, 0);
+ sqlite3VdbeOp3(v, OP_OpenRead, base+1, pIdx->tnum,
+ (char*)&pIdx->keyInfo, P3_KEYINFO);
+ if( seekOp==OP_Rewind ){
+ sqlite3VdbeAddOp(v, OP_String, 0, 0);
+ sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
+ seekOp = OP_MoveGt;
+ }
+ sqlite3VdbeAddOp(v, seekOp, base+1, 0);
+ sqlite3VdbeAddOp(v, OP_IdxRecno, base+1, 0);
+ sqlite3VdbeAddOp(v, OP_Close, base+1, 0);
+ sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
+ }
+ eList.nExpr = 1;
+ memset(&eListItem, 0, sizeof(eListItem));
+ eList.a = &eListItem;
+ eList.a[0].pExpr = pExpr;
+ selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, cont, cont, 0);
+ sqlite3VdbeResolveLabel(v, cont);
+ sqlite3VdbeAddOp(v, OP_Close, base, 0);
+
+ return 1;
+}
+
+/*
+** Analyze and ORDER BY or GROUP BY clause in a SELECT statement. Return
+** the number of errors seen.
+**
+** An ORDER BY or GROUP BY is a list of expressions. If any expression
+** is an integer constant, then that expression is replaced by the
+** corresponding entry in the result set.
+*/
+static int processOrderGroupBy(
+ Parse *pParse, /* Parsing context */
+ ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */
+ SrcList *pTabList, /* The FROM clause */
+ ExprList *pEList, /* The result set */
+ int isAgg, /* True if aggregate functions are involved */
+ const char *zType /* Either "ORDER" or "GROUP", as appropriate */
+){
+ int i;
+ if( pOrderBy==0 ) return 0;
+ for(i=0; i<pOrderBy->nExpr; i++){
+ int iCol;
+ Expr *pE = pOrderBy->a[i].pExpr;
+ if( sqlite3ExprIsInteger(pE, &iCol) && iCol>0 && iCol<=pEList->nExpr ){
+ sqlite3ExprDelete(pE);
+ pE = pOrderBy->a[i].pExpr = sqlite3ExprDup(pEList->a[iCol-1].pExpr);
+ }
+ if( sqlite3ExprResolveAndCheck(pParse, pTabList, pEList, pE, isAgg, 0) ){
+ return 1;
+ }
+ if( sqlite3ExprIsConstant(pE) ){
+ if( sqlite3ExprIsInteger(pE, &iCol)==0 ){
+ sqlite3ErrorMsg(pParse,
+ "%s BY terms must not be non-integer constants", zType);
+ return 1;
+ }else if( iCol<=0 || iCol>pEList->nExpr ){
+ sqlite3ErrorMsg(pParse,
+ "%s BY column number %d out of range - should be "
+ "between 1 and %d", zType, iCol, pEList->nExpr);
+ return 1;
+ }
+ }
+ }
+ return 0;
+}
+
+/*
+** Generate code for the given SELECT statement.
+**
+** The results are distributed in various ways depending on the
+** value of eDest and iParm.
+**
+** eDest Value Result
+** ------------ -------------------------------------------
+** SRT_Callback Invoke the callback for each row of the result.
+**
+** SRT_Mem Store first result in memory cell iParm
+**
+** SRT_Set Store results as keys of table iParm.
+**
+** SRT_Union Store results as a key in a temporary table iParm
+**
+** SRT_Except Remove results from the temporary table iParm.
+**
+** SRT_Table Store results in temporary table iParm
+**
+** The table above is incomplete. Additional eDist value have be added
+** since this comment was written. See the selectInnerLoop() function for
+** a complete listing of the allowed values of eDest and their meanings.
+**
+** This routine returns the number of errors. If any errors are
+** encountered, then an appropriate error message is left in
+** pParse->zErrMsg.
+**
+** This routine does NOT free the Select structure passed in. The
+** calling function needs to do that.
+**
+** The pParent, parentTab, and *pParentAgg fields are filled in if this
+** SELECT is a subquery. This routine may try to combine this SELECT
+** with its parent to form a single flat query. In so doing, it might
+** change the parent query from a non-aggregate to an aggregate query.
+** For that reason, the pParentAgg flag is passed as a pointer, so it
+** can be changed.
+**
+** Example 1: The meaning of the pParent parameter.
+**
+** SELECT * FROM t1 JOIN (SELECT x, count(*) FROM t2) JOIN t3;
+** \ \_______ subquery _______/ /
+** \ /
+** \____________________ outer query ___________________/
+**
+** This routine is called for the outer query first. For that call,
+** pParent will be NULL. During the processing of the outer query, this
+** routine is called recursively to handle the subquery. For the recursive
+** call, pParent will point to the outer query. Because the subquery is
+** the second element in a three-way join, the parentTab parameter will
+** be 1 (the 2nd value of a 0-indexed array.)
+*/
+int sqlite3Select(
+ Parse *pParse, /* The parser context */
+ Select *p, /* The SELECT statement being coded. */
+ int eDest, /* How to dispose of the results */
+ int iParm, /* A parameter used by the eDest disposal method */
+ Select *pParent, /* Another SELECT for which this is a sub-query */
+ int parentTab, /* Index in pParent->pSrc of this query */
+ int *pParentAgg, /* True if pParent uses aggregate functions */
+ char *aff /* If eDest is SRT_Union, the affinity string */
+){
+ int i;
+ WhereInfo *pWInfo;
+ Vdbe *v;
+ int isAgg = 0; /* True for select lists like "count(*)" */
+ ExprList *pEList; /* List of columns to extract. */
+ SrcList *pTabList; /* List of tables to select from */
+ Expr *pWhere; /* The WHERE clause. May be NULL */
+ ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
+ ExprList *pGroupBy; /* The GROUP BY clause. May be NULL */
+ Expr *pHaving; /* The HAVING clause. May be NULL */
+ int isDistinct; /* True if the DISTINCT keyword is present */
+ int distinct; /* Table to use for the distinct set */
+ int rc = 1; /* Value to return from this function */
+
+ if( sqlite3_malloc_failed || pParse->nErr || p==0 ) return 1;
+ if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
+
+ /* If there is are a sequence of queries, do the earlier ones first.
+ */
+ if( p->pPrior ){
+ return multiSelect(pParse, p, eDest, iParm, aff);
+ }
+
+ /* Make local copies of the parameters for this query.
+ */
+ pTabList = p->pSrc;
+ pWhere = p->pWhere;
+ pOrderBy = p->pOrderBy;
+ pGroupBy = p->pGroupBy;
+ pHaving = p->pHaving;
+ isDistinct = p->isDistinct;
+
+ /* Allocate VDBE cursors for each table in the FROM clause
+ */
+ sqlite3SrcListAssignCursors(pParse, pTabList);
+
+ /*
+ ** Do not even attempt to generate any code if we have already seen
+ ** errors before this routine starts.
+ */
+ if( pParse->nErr>0 ) goto select_end;
+
+ /* Expand any "*" terms in the result set. (For example the "*" in
+ ** "SELECT * FROM t1") The fillInColumnlist() routine also does some
+ ** other housekeeping - see the header comment for details.
+ */
+ if( fillInColumnList(pParse, p) ){
+ goto select_end;
+ }
+ pWhere = p->pWhere;
+ pEList = p->pEList;
+ if( pEList==0 ) goto select_end;
+
+ /* If writing to memory or generating a set
+ ** only a single column may be output.
+ */
+ if( (eDest==SRT_Mem || eDest==SRT_Set) && pEList->nExpr>1 ){
+ sqlite3ErrorMsg(pParse, "only a single result allowed for "
+ "a SELECT that is part of an expression");
+ goto select_end;
+ }
+
+ /* ORDER BY is ignored for some destinations.
+ */
+ switch( eDest ){
+ case SRT_Union:
+ case SRT_Except:
+ case SRT_Discard:
+ pOrderBy = 0;
+ break;
+ default:
+ break;
+ }
+
+ /* At this point, we should have allocated all the cursors that we
+ ** need to handle subquerys and temporary tables.
+ **
+ ** Resolve the column names and do a semantics check on all the expressions.
+ */
+ for(i=0; i<pEList->nExpr; i++){
+ if( sqlite3ExprResolveAndCheck(pParse, pTabList, 0, pEList->a[i].pExpr,
+ 1, &isAgg) ){
+ goto select_end;
+ }
+ }
+ if( sqlite3ExprResolveAndCheck(pParse, pTabList, pEList, pWhere, 0, 0) ){
+ goto select_end;
+ }
+ if( pHaving ){
+ if( pGroupBy==0 ){
+ sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
+ goto select_end;
+ }
+ if( sqlite3ExprResolveAndCheck(pParse, pTabList, pEList,pHaving,1,&isAgg) ){
+ goto select_end;
+ }
+ }
+ if( processOrderGroupBy(pParse, pOrderBy, pTabList, pEList, isAgg, "ORDER")
+ || processOrderGroupBy(pParse, pGroupBy, pTabList, pEList, isAgg, "GROUP")
+ ){
+ goto select_end;
+ }
+
+ /* Begin generating code.
+ */
+ v = sqlite3GetVdbe(pParse);
+ if( v==0 ) goto select_end;
+
+ /* Identify column names if we will be using them in a callback. This
+ ** step is skipped if the output is going to some other destination.
+ */
+ if( eDest==SRT_Callback ){
+ generateColumnNames(pParse, pTabList, pEList);
+ }
+
+ /* Generate code for all sub-queries in the FROM clause
+ */
+ for(i=0; i<pTabList->nSrc; i++){
+ const char *zSavedAuthContext = 0;
+ int needRestoreContext;
+
+ if( pTabList->a[i].pSelect==0 ) continue;
+ if( pTabList->a[i].zName!=0 ){
+ zSavedAuthContext = pParse->zAuthContext;
+ pParse->zAuthContext = pTabList->a[i].zName;
+ needRestoreContext = 1;
+ }else{
+ needRestoreContext = 0;
+ }
+ sqlite3Select(pParse, pTabList->a[i].pSelect, SRT_TempTable,
+ pTabList->a[i].iCursor, p, i, &isAgg, 0);
+ if( needRestoreContext ){
+ pParse->zAuthContext = zSavedAuthContext;
+ }
+ pTabList = p->pSrc;
+ pWhere = p->pWhere;
+ if( eDest!=SRT_Union && eDest!=SRT_Except && eDest!=SRT_Discard ){
+ pOrderBy = p->pOrderBy;
+ }
+ pGroupBy = p->pGroupBy;
+ pHaving = p->pHaving;
+ isDistinct = p->isDistinct;
+ }
+
+ /* Check for the special case of a min() or max() function by itself
+ ** in the result set.
+ */
+ if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
+ rc = 0;
+ goto select_end;
+ }
+
+ /* Check to see if this is a subquery that can be "flattened" into its parent.
+ ** If flattening is a possiblity, do so and return immediately.
+ */
+ if( pParent && pParentAgg &&
+ flattenSubquery(pParse, pParent, parentTab, *pParentAgg, isAgg) ){
+ if( isAgg ) *pParentAgg = 1;
+ return rc;
+ }
+
+ /* If there is an ORDER BY clause, resolve any collation sequences
+ ** names that have been explicitly specified.
+ */
+ if( pOrderBy ){
+ for(i=0; i<pOrderBy->nExpr; i++){
+ if( pOrderBy->a[i].zName ){
+ pOrderBy->a[i].pExpr->pColl =
+ sqlite3LocateCollSeq(pParse, pOrderBy->a[i].zName, -1);
+ }
+ }
+ if( pParse->nErr ){
+ goto select_end;
+ }
+ }
+
+ /* Set the limiter.
+ */
+ computeLimitRegisters(pParse, p);
+
+ /* If the output is destined for a temporary table, open that table.
+ */
+ if( eDest==SRT_TempTable ){
+ sqlite3VdbeAddOp(v, OP_OpenTemp, iParm, 0);
+ sqlite3VdbeAddOp(v, OP_SetNumColumns, iParm, pEList->nExpr);
+ }
+
+ /* Do an analysis of aggregate expressions.
+ */
+ sqliteAggregateInfoReset(pParse);
+ if( isAgg || pGroupBy ){
+ assert( pParse->nAgg==0 );
+ isAgg = 1;
+ for(i=0; i<pEList->nExpr; i++){
+ if( sqlite3ExprAnalyzeAggregates(pParse, pEList->a[i].pExpr) ){
+ goto select_end;
+ }
+ }
+ if( pGroupBy ){
+ for(i=0; i<pGroupBy->nExpr; i++){
+ if( sqlite3ExprAnalyzeAggregates(pParse, pGroupBy->a[i].pExpr) ){
+ goto select_end;
+ }
+ }
+ }
+ if( pHaving && sqlite3ExprAnalyzeAggregates(pParse, pHaving) ){
+ goto select_end;
+ }
+ if( pOrderBy ){
+ for(i=0; i<pOrderBy->nExpr; i++){
+ if( sqlite3ExprAnalyzeAggregates(pParse, pOrderBy->a[i].pExpr) ){
+ goto select_end;
+ }
+ }
+ }
+ }
+
+ /* Reset the aggregator
+ */
+ if( isAgg ){
+ int addr = sqlite3VdbeAddOp(v, OP_AggReset, (pGroupBy?0:1), pParse->nAgg);
+ for(i=0; i<pParse->nAgg; i++){
+ FuncDef *pFunc;
+ if( (pFunc = pParse->aAgg[i].pFunc)!=0 && pFunc->xFinalize!=0 ){
+ sqlite3VdbeOp3(v, OP_AggInit, 0, i, (char*)pFunc, P3_FUNCDEF);
+ }
+ }
+ if( pGroupBy ){
+ int sz = sizeof(KeyInfo) + pGroupBy->nExpr*sizeof(CollSeq*);
+ KeyInfo *pKey = (KeyInfo *)sqliteMalloc(sz);
+ if( 0==pKey ){
+ goto select_end;
+ }
+ pKey->enc = pParse->db->enc;
+ pKey->nField = pGroupBy->nExpr;
+ for(i=0; i<pGroupBy->nExpr; i++){
+ pKey->aColl[i] = sqlite3ExprCollSeq(pParse, pGroupBy->a[i].pExpr);
+ if( !pKey->aColl[i] ){
+ pKey->aColl[i] = pParse->db->pDfltColl;
+ }
+ }
+ sqlite3VdbeChangeP3(v, addr, (char *)pKey, P3_KEYINFO_HANDOFF);
+ }
+ }
+
+ /* Initialize the memory cell to NULL
+ */
+ if( eDest==SRT_Mem ){
+ sqlite3VdbeAddOp(v, OP_String8, 0, 0);
+ sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
+ }
+
+ /* Open a temporary table to use for the distinct set.
+ */
+ if( isDistinct ){
+ distinct = pParse->nTab++;
+ openTempIndex(pParse, p, distinct, 0);
+ }else{
+ distinct = -1;
+ }
+
+ /* Begin the database scan
+ */
+ pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
+ pGroupBy ? 0 : &pOrderBy);
+ if( pWInfo==0 ) goto select_end;
+
+ /* Use the standard inner loop if we are not dealing with
+ ** aggregates
+ */
+ if( !isAgg ){
+ if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
+ iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
+ goto select_end;
+ }
+ }
+
+ /* If we are dealing with aggregates, then do the special aggregate
+ ** processing.
+ */
+ else{
+ AggExpr *pAgg;
+ if( pGroupBy ){
+ int lbl1;
+ for(i=0; i<pGroupBy->nExpr; i++){
+ sqlite3ExprCode(pParse, pGroupBy->a[i].pExpr);
+ }
+ /* No affinity string is attached to the following OP_MakeRecord
+ ** because we do not need to do any coercion of datatypes. */
+ sqlite3VdbeAddOp(v, OP_MakeRecord, pGroupBy->nExpr, 0);
+ lbl1 = sqlite3VdbeMakeLabel(v);
+ sqlite3VdbeAddOp(v, OP_AggFocus, 0, lbl1);
+ for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
+ if( pAgg->isAgg ) continue;
+ sqlite3ExprCode(pParse, pAgg->pExpr);
+ sqlite3VdbeAddOp(v, OP_AggSet, 0, i);
+ }
+ sqlite3VdbeResolveLabel(v, lbl1);
+ }
+ for(i=0, pAgg=pParse->aAgg; i<pParse->nAgg; i++, pAgg++){
+ Expr *pE;
+ int nExpr;
+ FuncDef *pDef;
+ if( !pAgg->isAgg ) continue;
+ assert( pAgg->pFunc!=0 );
+ assert( pAgg->pFunc->xStep!=0 );
+ pDef = pAgg->pFunc;
+ pE = pAgg->pExpr;
+ assert( pE!=0 );
+ assert( pE->op==TK_AGG_FUNCTION );
+ nExpr = sqlite3ExprCodeExprList(pParse, pE->pList);
+ sqlite3VdbeAddOp(v, OP_Integer, i, 0);
+ if( pDef->needCollSeq ){
+ CollSeq *pColl = 0;
+ int j;
+ for(j=0; !pColl && j<nExpr; j++){
+ pColl = sqlite3ExprCollSeq(pParse, pE->pList->a[j].pExpr);
+ }
+ if( !pColl ) pColl = pParse->db->pDfltColl;
+ sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
+ }
+ sqlite3VdbeOp3(v, OP_AggFunc, 0, nExpr, (char*)pDef, P3_POINTER);
+ }
+ }
+
+ /* End the database scan loop.
+ */
+ sqlite3WhereEnd(pWInfo);
+
+ /* If we are processing aggregates, we need to set up a second loop
+ ** over all of the aggregate values and process them.
+ */
+ if( isAgg ){
+ int endagg = sqlite3VdbeMakeLabel(v);
+ int startagg;
+ startagg = sqlite3VdbeAddOp(v, OP_AggNext, 0, endagg);
+ pParse->useAgg = 1;
+ if( pHaving ){
+ sqlite3ExprIfFalse(pParse, pHaving, startagg, 1);
+ }
+ if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
+ iParm, startagg, endagg, aff) ){
+ goto select_end;
+ }
+ sqlite3VdbeAddOp(v, OP_Goto, 0, startagg);
+ sqlite3VdbeResolveLabel(v, endagg);
+ sqlite3VdbeAddOp(v, OP_Noop, 0, 0);
+ pParse->useAgg = 0;
+ }
+
+ /* If there is an ORDER BY clause, then we need to sort the results
+ ** and send them to the callback one by one.
+ */
+ if( pOrderBy ){
+ generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
+ }
+
+ /* If this was a subquery, we have now converted the subquery into a
+ ** temporary table. So delete the subquery structure from the parent
+ ** to prevent this subquery from being evaluated again and to force the
+ ** the use of the temporary table.
+ */
+ if( pParent ){
+ assert( pParent->pSrc->nSrc>parentTab );
+ assert( pParent->pSrc->a[parentTab].pSelect==p );
+ sqlite3SelectDelete(p);
+ pParent->pSrc->a[parentTab].pSelect = 0;
+ }
+
+ /* The SELECT was successfully coded. Set the return code to 0
+ ** to indicate no errors.
+ */
+ rc = 0;
+
+ /* Control jumps to here if an error is encountered above, or upon
+ ** successful coding of the SELECT.
+ */
+select_end:
+ sqliteAggregateInfoReset(pParse);
+ return rc;
+}