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-/*
-** 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 module contains C code that generates VDBE code used to process
-** the WHERE clause of SQL statements.
-**
-** $Id$
-*/
-#include "sqliteInt.h"
-
-/*
-** The query generator uses an array of instances of this structure to
-** help it analyze the subexpressions of the WHERE clause. Each WHERE
-** clause subexpression is separated from the others by an AND operator.
-*/
-typedef struct ExprInfo ExprInfo;
-struct ExprInfo {
- Expr *p; /* Pointer to the subexpression */
- u8 indexable; /* True if this subexprssion is usable by an index */
- short int idxLeft; /* p->pLeft is a column in this table number. -1 if
- ** p->pLeft is not the column of any table */
- short int idxRight; /* p->pRight is a column in this table number. -1 if
- ** p->pRight is not the column of any table */
- unsigned prereqLeft; /* Bitmask of tables referenced by p->pLeft */
- unsigned prereqRight; /* Bitmask of tables referenced by p->pRight */
- unsigned prereqAll; /* Bitmask of tables referenced by p */
-};
-
-/*
-** An instance of the following structure keeps track of a mapping
-** between VDBE cursor numbers and bitmasks. The VDBE cursor numbers
-** are small integers contained in SrcList_item.iCursor and Expr.iTable
-** fields. For any given WHERE clause, we want to track which cursors
-** are being used, so we assign a single bit in a 32-bit word to track
-** that cursor. Then a 32-bit integer is able to show the set of all
-** cursors being used.
-*/
-typedef struct ExprMaskSet ExprMaskSet;
-struct ExprMaskSet {
- int n; /* Number of assigned cursor values */
- int ix[31]; /* Cursor assigned to each bit */
-};
-
-/*
-** Determine the number of elements in an array.
-*/
-#define ARRAYSIZE(X) (sizeof(X)/sizeof(X[0]))
-
-/*
-** This routine is used to divide the WHERE expression into subexpressions
-** separated by the AND operator.
-**
-** aSlot[] is an array of subexpressions structures.
-** There are nSlot spaces left in this array. This routine attempts to
-** split pExpr into subexpressions and fills aSlot[] with those subexpressions.
-** The return value is the number of slots filled.
-*/
-static int exprSplit(int nSlot, ExprInfo *aSlot, Expr *pExpr){
- int cnt = 0;
- if( pExpr==0 || nSlot<1 ) return 0;
- if( nSlot==1 || pExpr->op!=TK_AND ){
- aSlot[0].p = pExpr;
- return 1;
- }
- if( pExpr->pLeft->op!=TK_AND ){
- aSlot[0].p = pExpr->pLeft;
- cnt = 1 + exprSplit(nSlot-1, &aSlot[1], pExpr->pRight);
- }else{
- cnt = exprSplit(nSlot, aSlot, pExpr->pLeft);
- cnt += exprSplit(nSlot-cnt, &aSlot[cnt], pExpr->pRight);
- }
- return cnt;
-}
-
-/*
-** Initialize an expression mask set
-*/
-#define initMaskSet(P) memset(P, 0, sizeof(*P))
-
-/*
-** Return the bitmask for the given cursor. Assign a new bitmask
-** if this is the first time the cursor has been seen.
-*/
-static int getMask(ExprMaskSet *pMaskSet, int iCursor){
- int i;
- for(i=0; i<pMaskSet->n; i++){
- if( pMaskSet->ix[i]==iCursor ) return 1<<i;
- }
- if( i==pMaskSet->n && i<ARRAYSIZE(pMaskSet->ix) ){
- pMaskSet->n++;
- pMaskSet->ix[i] = iCursor;
- return 1<<i;
- }
- return 0;
-}
-
-/*
-** Destroy an expression mask set
-*/
-#define freeMaskSet(P) /* NO-OP */
-
-/*
-** This routine walks (recursively) an expression tree and generates
-** a bitmask indicating which tables are used in that expression
-** tree.
-**
-** In order for this routine to work, the calling function must have
-** previously invoked sqlite3ExprResolveIds() on the expression. See
-** the header comment on that routine for additional information.
-** The sqlite3ExprResolveIds() routines looks for column names and
-** sets their opcodes to TK_COLUMN and their Expr.iTable fields to
-** the VDBE cursor number of the table.
-*/
-static int exprTableUsage(ExprMaskSet *pMaskSet, Expr *p){
- unsigned int mask = 0;
- if( p==0 ) return 0;
- if( p->op==TK_COLUMN ){
- mask = getMask(pMaskSet, p->iTable);
- if( mask==0 ) mask = -1;
- return mask;
- }
- if( p->pRight ){
- mask = exprTableUsage(pMaskSet, p->pRight);
- }
- if( p->pLeft ){
- mask |= exprTableUsage(pMaskSet, p->pLeft);
- }
- if( p->pList ){
- int i;
- for(i=0; i<p->pList->nExpr; i++){
- mask |= exprTableUsage(pMaskSet, p->pList->a[i].pExpr);
- }
- }
- return mask;
-}
-
-/*
-** Return TRUE if the given operator is one of the operators that is
-** allowed for an indexable WHERE clause. The allowed operators are
-** "=", "<", ">", "<=", ">=", and "IN".
-*/
-static int allowedOp(int op){
- assert( TK_GT==TK_LE-1 && TK_LE==TK_LT-1 && TK_LT==TK_GE-1 && TK_EQ==TK_GT-1);
- return op==TK_IN || (op>=TK_EQ && op<=TK_GE);
-}
-
-/*
-** Swap two integers.
-*/
-#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
-
-/*
-** Return the index in the SrcList that uses cursor iCur. If iCur is
-** used by the first entry in SrcList return 0. If iCur is used by
-** the second entry return 1. And so forth.
-**
-** SrcList is the set of tables in the FROM clause in the order that
-** they will be processed. The value returned here gives us an index
-** of which tables will be processed first.
-*/
-static int tableOrder(SrcList *pList, int iCur){
- int i;
- for(i=0; i<pList->nSrc; i++){
- if( pList->a[i].iCursor==iCur ) return i;
- }
- return -1;
-}
-
-/*
-** The input to this routine is an ExprInfo structure with only the
-** "p" field filled in. The job of this routine is to analyze the
-** subexpression and populate all the other fields of the ExprInfo
-** structure.
-*/
-static void exprAnalyze(SrcList *pSrc, ExprMaskSet *pMaskSet, ExprInfo *pInfo){
- Expr *pExpr = pInfo->p;
- pInfo->prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
- pInfo->prereqRight = exprTableUsage(pMaskSet, pExpr->pRight);
- pInfo->prereqAll = exprTableUsage(pMaskSet, pExpr);
- pInfo->indexable = 0;
- pInfo->idxLeft = -1;
- pInfo->idxRight = -1;
- if( allowedOp(pExpr->op) && (pInfo->prereqRight & pInfo->prereqLeft)==0 ){
- if( pExpr->pRight && pExpr->pRight->op==TK_COLUMN ){
- pInfo->idxRight = pExpr->pRight->iTable;
- pInfo->indexable = 1;
- }
- if( pExpr->pLeft->op==TK_COLUMN ){
- pInfo->idxLeft = pExpr->pLeft->iTable;
- pInfo->indexable = 1;
- }
- }
- if( pInfo->indexable ){
- assert( pInfo->idxLeft!=pInfo->idxRight );
-
- /* We want the expression to be of the form "X = expr", not "expr = X".
- ** So flip it over if necessary. If the expression is "X = Y", then
- ** we want Y to come from an earlier table than X.
- **
- ** The collating sequence rule is to always choose the left expression.
- ** So if we do a flip, we also have to move the collating sequence.
- */
- if( tableOrder(pSrc,pInfo->idxLeft)<tableOrder(pSrc,pInfo->idxRight) ){
- assert( pExpr->op!=TK_IN );
- SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl);
- SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
- if( pExpr->op>=TK_GT ){
- assert( TK_LT==TK_GT+2 );
- assert( TK_GE==TK_LE+2 );
- assert( TK_GT>TK_EQ );
- assert( TK_GT<TK_LE );
- assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
- pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
- }
- SWAP(unsigned, pInfo->prereqLeft, pInfo->prereqRight);
- SWAP(short int, pInfo->idxLeft, pInfo->idxRight);
- }
- }
-
-}
-
-/*
-** pOrderBy is an ORDER BY clause from a SELECT statement. pTab is the
-** left-most table in the FROM clause of that same SELECT statement and
-** the table has a cursor number of "base".
-**
-** This routine attempts to find an index for pTab that generates the
-** correct record sequence for the given ORDER BY clause. The return value
-** is a pointer to an index that does the job. NULL is returned if the
-** table has no index that will generate the correct sort order.
-**
-** If there are two or more indices that generate the correct sort order
-** and pPreferredIdx is one of those indices, then return pPreferredIdx.
-**
-** nEqCol is the number of columns of pPreferredIdx that are used as
-** equality constraints. Any index returned must have exactly this same
-** set of columns. The ORDER BY clause only matches index columns beyond the
-** the first nEqCol columns.
-**
-** All terms of the ORDER BY clause must be either ASC or DESC. The
-** *pbRev value is set to 1 if the ORDER BY clause is all DESC and it is
-** set to 0 if the ORDER BY clause is all ASC.
-*/
-static Index *findSortingIndex(
- Parse *pParse,
- Table *pTab, /* The table to be sorted */
- int base, /* Cursor number for pTab */
- ExprList *pOrderBy, /* The ORDER BY clause */
- Index *pPreferredIdx, /* Use this index, if possible and not NULL */
- int nEqCol, /* Number of index columns used with == constraints */
- int *pbRev /* Set to 1 if ORDER BY is DESC */
-){
- int i, j;
- Index *pMatch;
- Index *pIdx;
- int sortOrder;
- sqlite3 *db = pParse->db;
-
- assert( pOrderBy!=0 );
- assert( pOrderBy->nExpr>0 );
- sortOrder = pOrderBy->a[0].sortOrder;
- for(i=0; i<pOrderBy->nExpr; i++){
- Expr *p;
- if( pOrderBy->a[i].sortOrder!=sortOrder ){
- /* Indices can only be used if all ORDER BY terms are either
- ** DESC or ASC. Indices cannot be used on a mixture. */
- return 0;
- }
- p = pOrderBy->a[i].pExpr;
- if( p->op!=TK_COLUMN || p->iTable!=base ){
- /* Can not use an index sort on anything that is not a column in the
- ** left-most table of the FROM clause */
- return 0;
- }
- }
-
- /* If we get this far, it means the ORDER BY clause consists only of
- ** ascending columns in the left-most table of the FROM clause. Now
- ** check for a matching index.
- */
- pMatch = 0;
- for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
- int nExpr = pOrderBy->nExpr;
- if( pIdx->nColumn < nEqCol || pIdx->nColumn < nExpr ) continue;
- for(i=j=0; i<nEqCol; i++){
- CollSeq *pColl = sqlite3ExprCollSeq(pParse, pOrderBy->a[j].pExpr);
- if( !pColl ) pColl = db->pDfltColl;
- if( pPreferredIdx->aiColumn[i]!=pIdx->aiColumn[i] ) break;
- if( pPreferredIdx->keyInfo.aColl[i]!=pIdx->keyInfo.aColl[i] ) break;
- if( j<nExpr &&
- pOrderBy->a[j].pExpr->iColumn==pIdx->aiColumn[i] &&
- pColl==pIdx->keyInfo.aColl[i]
- ){
- j++;
- }
- }
- if( i<nEqCol ) continue;
- for(i=0; i+j<nExpr; i++){
- CollSeq *pColl = sqlite3ExprCollSeq(pParse, pOrderBy->a[i+j].pExpr);
- if( !pColl ) pColl = db->pDfltColl;
- if( pOrderBy->a[i+j].pExpr->iColumn!=pIdx->aiColumn[i+nEqCol] ||
- pColl!=pIdx->keyInfo.aColl[i+nEqCol] ) break;
- }
- if( i+j>=nExpr ){
- pMatch = pIdx;
- if( pIdx==pPreferredIdx ) break;
- }
- }
- if( pMatch && pbRev ){
- *pbRev = sortOrder==SQLITE_SO_DESC;
- }
- return pMatch;
-}
-
-/*
-** Disable a term in the WHERE clause. Except, do not disable the term
-** if it controls a LEFT OUTER JOIN and it did not originate in the ON
-** or USING clause of that join.
-**
-** Consider the term t2.z='ok' in the following queries:
-**
-** (1) SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x WHERE t2.z='ok'
-** (2) SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.x AND t2.z='ok'
-** (3) SELECT * FROM t1, t2 WHERE t1.a=t2.x AND t2.z='ok'
-**
-** The t2.z='ok' is disabled in the in (2) because it did not originate
-** in the ON clause. The term is disabled in (3) because it is not part
-** of a LEFT OUTER JOIN. In (1), the term is not disabled.
-**
-** Disabling a term causes that term to not be tested in the inner loop
-** of the join. Disabling is an optimization. We would get the correct
-** results if nothing were ever disabled, but joins might run a little
-** slower. The trick is to disable as much as we can without disabling
-** too much. If we disabled in (1), we'd get the wrong answer.
-** See ticket #813.
-*/
-static void disableTerm(WhereLevel *pLevel, Expr **ppExpr){
- Expr *pExpr = *ppExpr;
- if( pLevel->iLeftJoin==0 || ExprHasProperty(pExpr, EP_FromJoin) ){
- *ppExpr = 0;
- }
-}
-
-/*
-** Generate code that builds a probe for an index. Details:
-**
-** * Check the top nColumn entries on the stack. If any
-** of those entries are NULL, jump immediately to brk,
-** which is the loop exit, since no index entry will match
-** if any part of the key is NULL.
-**
-** * Construct a probe entry from the top nColumn entries in
-** the stack with affinities appropriate for index pIdx.
-*/
-static void buildIndexProbe(Vdbe *v, int nColumn, int brk, Index *pIdx){
- sqlite3VdbeAddOp(v, OP_NotNull, -nColumn, sqlite3VdbeCurrentAddr(v)+3);
- sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
- sqlite3VdbeAddOp(v, OP_Goto, 0, brk);
- sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
- sqlite3IndexAffinityStr(v, pIdx);
-}
-
-/*
-** Generate code for an equality term of the WHERE clause. An equality
-** term can be either X=expr or X IN (...). pTerm is the X.
-*/
-static void codeEqualityTerm(
- Parse *pParse, /* The parsing context */
- ExprInfo *pTerm, /* The term of the WHERE clause to be coded */
- int brk, /* Jump here to abandon the loop */
- WhereLevel *pLevel /* When level of the FROM clause we are working on */
-){
- Expr *pX = pTerm->p;
- if( pX->op!=TK_IN ){
- assert( pX->op==TK_EQ );
- sqlite3ExprCode(pParse, pX->pRight);
- }else{
- int iTab = pX->iTable;
- Vdbe *v = pParse->pVdbe;
- sqlite3VdbeAddOp(v, OP_Rewind, iTab, brk);
- sqlite3VdbeAddOp(v, OP_KeyAsData, iTab, 1);
- pLevel->inP2 = sqlite3VdbeAddOp(v, OP_IdxColumn, iTab, 0);
- pLevel->inOp = OP_Next;
- pLevel->inP1 = iTab;
- }
- disableTerm(pLevel, &pTerm->p);
-}
-
-
-/*
-** Generate the beginning of the loop used for WHERE clause processing.
-** The return value is a pointer to an (opaque) structure that contains
-** information needed to terminate the loop. Later, the calling routine
-** should invoke sqlite3WhereEnd() with the return value of this function
-** in order to complete the WHERE clause processing.
-**
-** If an error occurs, this routine returns NULL.
-**
-** The basic idea is to do a nested loop, one loop for each table in
-** the FROM clause of a select. (INSERT and UPDATE statements are the
-** same as a SELECT with only a single table in the FROM clause.) For
-** example, if the SQL is this:
-**
-** SELECT * FROM t1, t2, t3 WHERE ...;
-**
-** Then the code generated is conceptually like the following:
-**
-** foreach row1 in t1 do \ Code generated
-** foreach row2 in t2 do |-- by sqlite3WhereBegin()
-** foreach row3 in t3 do /
-** ...
-** end \ Code generated
-** end |-- by sqlite3WhereEnd()
-** end /
-**
-** There are Btree cursors associated with each table. t1 uses cursor
-** number pTabList->a[0].iCursor. t2 uses the cursor pTabList->a[1].iCursor.
-** And so forth. This routine generates code to open those VDBE cursors
-** and sqlite3WhereEnd() generates the code to close them.
-**
-** If the WHERE clause is empty, the foreach loops must each scan their
-** entire tables. Thus a three-way join is an O(N^3) operation. But if
-** the tables have indices and there are terms in the WHERE clause that
-** refer to those indices, a complete table scan can be avoided and the
-** code will run much faster. Most of the work of this routine is checking
-** to see if there are indices that can be used to speed up the loop.
-**
-** Terms of the WHERE clause are also used to limit which rows actually
-** make it to the "..." in the middle of the loop. After each "foreach",
-** terms of the WHERE clause that use only terms in that loop and outer
-** loops are evaluated and if false a jump is made around all subsequent
-** inner loops (or around the "..." if the test occurs within the inner-
-** most loop)
-**
-** OUTER JOINS
-**
-** An outer join of tables t1 and t2 is conceptally coded as follows:
-**
-** foreach row1 in t1 do
-** flag = 0
-** foreach row2 in t2 do
-** start:
-** ...
-** flag = 1
-** end
-** if flag==0 then
-** move the row2 cursor to a null row
-** goto start
-** fi
-** end
-**
-** ORDER BY CLAUSE PROCESSING
-**
-** *ppOrderBy is a pointer to the ORDER BY clause of a SELECT statement,
-** if there is one. If there is no ORDER BY clause or if this routine
-** is called from an UPDATE or DELETE statement, then ppOrderBy is NULL.
-**
-** If an index can be used so that the natural output order of the table
-** scan is correct for the ORDER BY clause, then that index is used and
-** *ppOrderBy is set to NULL. This is an optimization that prevents an
-** unnecessary sort of the result set if an index appropriate for the
-** ORDER BY clause already exists.
-**
-** If the where clause loops cannot be arranged to provide the correct
-** output order, then the *ppOrderBy is unchanged.
-*/
-WhereInfo *sqlite3WhereBegin(
- Parse *pParse, /* The parser context */
- SrcList *pTabList, /* A list of all tables to be scanned */
- Expr *pWhere, /* The WHERE clause */
- int pushKey, /* If TRUE, leave the table key on the stack */
- ExprList **ppOrderBy /* An ORDER BY clause, or NULL */
-){
- int i; /* Loop counter */
- WhereInfo *pWInfo; /* Will become the return value of this function */
- Vdbe *v = pParse->pVdbe; /* The virtual database engine */
- int brk, cont = 0; /* Addresses used during code generation */
- int nExpr; /* Number of subexpressions in the WHERE clause */
- int loopMask; /* One bit set for each outer loop */
- int haveKey = 0; /* True if KEY is on the stack */
- ExprInfo *pTerm; /* A single term in the WHERE clause; ptr to aExpr[] */
- ExprMaskSet maskSet; /* The expression mask set */
- int iDirectEq[32]; /* Term of the form ROWID==X for the N-th table */
- int iDirectLt[32]; /* Term of the form ROWID<X or ROWID<=X */
- int iDirectGt[32]; /* Term of the form ROWID>X or ROWID>=X */
- ExprInfo aExpr[101]; /* The WHERE clause is divided into these terms */
-
- /* pushKey is only allowed if there is a single table (as in an INSERT or
- ** UPDATE statement)
- */
- assert( pushKey==0 || pTabList->nSrc==1 );
-
- /* Split the WHERE clause into separate subexpressions where each
- ** subexpression is separated by an AND operator. If the aExpr[]
- ** array fills up, the last entry might point to an expression which
- ** contains additional unfactored AND operators.
- */
- initMaskSet(&maskSet);
- memset(aExpr, 0, sizeof(aExpr));
- nExpr = exprSplit(ARRAYSIZE(aExpr), aExpr, pWhere);
- if( nExpr==ARRAYSIZE(aExpr) ){
- sqlite3ErrorMsg(pParse, "WHERE clause too complex - no more "
- "than %d terms allowed", (int)ARRAYSIZE(aExpr)-1);
- return 0;
- }
-
- /* Allocate and initialize the WhereInfo structure that will become the
- ** return value.
- */
- pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nSrc*sizeof(WhereLevel));
- if( sqlite3_malloc_failed ){
- /* sqliteFree(pWInfo); // Leak memory when malloc fails */
- return 0;
- }
- pWInfo->pParse = pParse;
- pWInfo->pTabList = pTabList;
- pWInfo->iBreak = sqlite3VdbeMakeLabel(v);
-
- /* Special case: a WHERE clause that is constant. Evaluate the
- ** expression and either jump over all of the code or fall thru.
- */
- if( pWhere && (pTabList->nSrc==0 || sqlite3ExprIsConstant(pWhere)) ){
- sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, 1);
- pWhere = 0;
- }
-
- /* Analyze all of the subexpressions.
- */
- for(pTerm=aExpr, i=0; i<nExpr; i++, pTerm++){
- TriggerStack *pStack;
- exprAnalyze(pTabList, &maskSet, pTerm);
-
- /* If we are executing a trigger body, remove all references to
- ** new.* and old.* tables from the prerequisite masks.
- */
- if( (pStack = pParse->trigStack)!=0 ){
- int x;
- if( (x=pStack->newIdx) >= 0 ){
- int mask = ~getMask(&maskSet, x);
- pTerm->prereqRight &= mask;
- pTerm->prereqLeft &= mask;
- pTerm->prereqAll &= mask;
- }
- if( (x=pStack->oldIdx) >= 0 ){
- int mask = ~getMask(&maskSet, x);
- pTerm->prereqRight &= mask;
- pTerm->prereqLeft &= mask;
- pTerm->prereqAll &= mask;
- }
- }
- }
-
- /* Figure out what index to use (if any) for each nested loop.
- ** Make pWInfo->a[i].pIdx point to the index to use for the i-th nested
- ** loop where i==0 is the outer loop and i==pTabList->nSrc-1 is the inner
- ** loop.
- **
- ** If terms exist that use the ROWID of any table, then set the
- ** iDirectEq[], iDirectLt[], or iDirectGt[] elements for that table
- ** to the index of the term containing the ROWID. We always prefer
- ** to use a ROWID which can directly access a table rather than an
- ** index which requires reading an index first to get the rowid then
- ** doing a second read of the actual database table.
- **
- ** Actually, if there are more than 32 tables in the join, only the
- ** first 32 tables are candidates for indices. This is (again) due
- ** to the limit of 32 bits in an integer bitmask.
- */
- loopMask = 0;
- for(i=0; i<pTabList->nSrc && i<ARRAYSIZE(iDirectEq); i++){
- int j;
- WhereLevel *pLevel = &pWInfo->a[i];
- int iCur = pTabList->a[i].iCursor; /* The cursor for this table */
- int mask = getMask(&maskSet, iCur); /* Cursor mask for this table */
- Table *pTab = pTabList->a[i].pTab;
- Index *pIdx;
- Index *pBestIdx = 0;
- int bestScore = 0;
-
- /* Check to see if there is an expression that uses only the
- ** ROWID field of this table. For terms of the form ROWID==expr
- ** set iDirectEq[i] to the index of the term. For terms of the
- ** form ROWID<expr or ROWID<=expr set iDirectLt[i] to the term index.
- ** For terms like ROWID>expr or ROWID>=expr set iDirectGt[i].
- **
- ** (Added:) Treat ROWID IN expr like ROWID=expr.
- */
- pLevel->iCur = -1;
- iDirectEq[i] = -1;
- iDirectLt[i] = -1;
- iDirectGt[i] = -1;
- for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
- Expr *pX = pTerm->p;
- if( pTerm->idxLeft==iCur && pX->pLeft->iColumn<0
- && (pTerm->prereqRight & loopMask)==pTerm->prereqRight ){
- switch( pX->op ){
- case TK_IN:
- case TK_EQ: iDirectEq[i] = j; break;
- case TK_LE:
- case TK_LT: iDirectLt[i] = j; break;
- case TK_GE:
- case TK_GT: iDirectGt[i] = j; break;
- }
- }
- }
- if( iDirectEq[i]>=0 ){
- loopMask |= mask;
- pLevel->pIdx = 0;
- continue;
- }
-
- /* Do a search for usable indices. Leave pBestIdx pointing to
- ** the "best" index. pBestIdx is left set to NULL if no indices
- ** are usable.
- **
- ** The best index is determined as follows. For each of the
- ** left-most terms that is fixed by an equality operator, add
- ** 8 to the score. The right-most term of the index may be
- ** constrained by an inequality. Add 1 if for an "x<..." constraint
- ** and add 2 for an "x>..." constraint. Chose the index that
- ** gives the best score.
- **
- ** This scoring system is designed so that the score can later be
- ** used to determine how the index is used. If the score&7 is 0
- ** then all constraints are equalities. If score&1 is not 0 then
- ** there is an inequality used as a termination key. (ex: "x<...")
- ** If score&2 is not 0 then there is an inequality used as the
- ** start key. (ex: "x>..."). A score or 4 is the special case
- ** of an IN operator constraint. (ex: "x IN ...").
- **
- ** The IN operator (as in "<expr> IN (...)") is treated the same as
- ** an equality comparison except that it can only be used on the
- ** left-most column of an index and other terms of the WHERE clause
- ** cannot be used in conjunction with the IN operator to help satisfy
- ** other columns of the index.
- */
- for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
- int eqMask = 0; /* Index columns covered by an x=... term */
- int ltMask = 0; /* Index columns covered by an x<... term */
- int gtMask = 0; /* Index columns covered by an x>... term */
- int inMask = 0; /* Index columns covered by an x IN .. term */
- int nEq, m, score;
-
- if( pIdx->nColumn>32 ) continue; /* Ignore indices too many columns */
- for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
- Expr *pX = pTerm->p;
- CollSeq *pColl = sqlite3ExprCollSeq(pParse, pX->pLeft);
- if( !pColl && pX->pRight ){
- pColl = sqlite3ExprCollSeq(pParse, pX->pRight);
- }
- if( !pColl ){
- pColl = pParse->db->pDfltColl;
- }
- if( pTerm->idxLeft==iCur
- && (pTerm->prereqRight & loopMask)==pTerm->prereqRight ){
- int iColumn = pX->pLeft->iColumn;
- int k;
- char idxaff = pIdx->pTable->aCol[iColumn].affinity;
- for(k=0; k<pIdx->nColumn; k++){
- /* If the collating sequences or affinities don't match,
- ** ignore this index. */
- if( pColl!=pIdx->keyInfo.aColl[k] ) continue;
- if( !sqlite3IndexAffinityOk(pX, idxaff) ) continue;
- if( pIdx->aiColumn[k]==iColumn ){
- switch( pX->op ){
- case TK_IN: {
- if( k==0 ) inMask |= 1;
- break;
- }
- case TK_EQ: {
- eqMask |= 1<<k;
- break;
- }
- case TK_LE:
- case TK_LT: {
- ltMask |= 1<<k;
- break;
- }
- case TK_GE:
- case TK_GT: {
- gtMask |= 1<<k;
- break;
- }
- default: {
- /* CANT_HAPPEN */
- assert( 0 );
- break;
- }
- }
- break;
- }
- }
- }
- }
-
- /* The following loop ends with nEq set to the number of columns
- ** on the left of the index with == constraints.
- */
- for(nEq=0; nEq<pIdx->nColumn; nEq++){
- m = (1<<(nEq+1))-1;
- if( (m & eqMask)!=m ) break;
- }
- score = nEq*8; /* Base score is 8 times number of == constraints */
- m = 1<<nEq;
- if( m & ltMask ) score++; /* Increase score for a < constraint */
- if( m & gtMask ) score+=2; /* Increase score for a > constraint */
- if( score==0 && inMask ) score = 4; /* Default score for IN constraint */
- if( score>bestScore ){
- pBestIdx = pIdx;
- bestScore = score;
- }
- }
- pLevel->pIdx = pBestIdx;
- pLevel->score = bestScore;
- pLevel->bRev = 0;
- loopMask |= mask;
- if( pBestIdx ){
- pLevel->iCur = pParse->nTab++;
- }
- }
-
- /* Check to see if the ORDER BY clause is or can be satisfied by the
- ** use of an index on the first table.
- */
- if( ppOrderBy && *ppOrderBy && pTabList->nSrc>0 ){
- Index *pSortIdx;
- Index *pIdx;
- Table *pTab;
- int bRev = 0;
-
- pTab = pTabList->a[0].pTab;
- pIdx = pWInfo->a[0].pIdx;
- if( pIdx && pWInfo->a[0].score==4 ){
- /* If there is already an IN index on the left-most table,
- ** it will not give the correct sort order.
- ** So, pretend that no suitable index is found.
- */
- pSortIdx = 0;
- }else if( iDirectEq[0]>=0 || iDirectLt[0]>=0 || iDirectGt[0]>=0 ){
- /* If the left-most column is accessed using its ROWID, then do
- ** not try to sort by index.
- */
- pSortIdx = 0;
- }else{
- int nEqCol = (pWInfo->a[0].score+4)/8;
- pSortIdx = findSortingIndex(pParse, pTab, pTabList->a[0].iCursor,
- *ppOrderBy, pIdx, nEqCol, &bRev);
- }
- if( pSortIdx && (pIdx==0 || pIdx==pSortIdx) ){
- if( pIdx==0 ){
- pWInfo->a[0].pIdx = pSortIdx;
- pWInfo->a[0].iCur = pParse->nTab++;
- }
- pWInfo->a[0].bRev = bRev;
- *ppOrderBy = 0;
- }
- }
-
- /* Open all tables in the pTabList and all indices used by those tables.
- */
- sqlite3CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
- for(i=0; i<pTabList->nSrc; i++){
- Table *pTab;
- Index *pIx;
-
- pTab = pTabList->a[i].pTab;
- if( pTab->isTransient || pTab->pSelect ) continue;
- sqlite3OpenTableForReading(v, pTabList->a[i].iCursor, pTab);
- sqlite3CodeVerifySchema(pParse, pTab->iDb);
- if( (pIx = pWInfo->a[i].pIdx)!=0 ){
- sqlite3VdbeAddOp(v, OP_Integer, pIx->iDb, 0);
- sqlite3VdbeOp3(v, OP_OpenRead, pWInfo->a[i].iCur, pIx->tnum,
- (char*)&pIx->keyInfo, P3_KEYINFO);
- }
- }
-
- /* Generate the code to do the search
- */
- loopMask = 0;
- for(i=0; i<pTabList->nSrc; i++){
- int j, k;
- int iCur = pTabList->a[i].iCursor;
- Index *pIdx;
- WhereLevel *pLevel = &pWInfo->a[i];
-
- /* If this is the right table of a LEFT OUTER JOIN, allocate and
- ** initialize a memory cell that records if this table matches any
- ** row of the left table of the join.
- */
- if( i>0 && (pTabList->a[i-1].jointype & JT_LEFT)!=0 ){
- if( !pParse->nMem ) pParse->nMem++;
- pLevel->iLeftJoin = pParse->nMem++;
- sqlite3VdbeAddOp(v, OP_String8, 0, 0);
- sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
- VdbeComment((v, "# init LEFT JOIN no-match flag"));
- }
-
- pIdx = pLevel->pIdx;
- pLevel->inOp = OP_Noop;
- if( i<ARRAYSIZE(iDirectEq) && (k = iDirectEq[i])>=0 ){
- /* Case 1: We can directly reference a single row using an
- ** equality comparison against the ROWID field. Or
- ** we reference multiple rows using a "rowid IN (...)"
- ** construct.
- */
- assert( k<nExpr );
- pTerm = &aExpr[k];
- assert( pTerm->p!=0 );
- assert( pTerm->idxLeft==iCur );
- brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
- codeEqualityTerm(pParse, pTerm, brk, pLevel);
- cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
- sqlite3VdbeAddOp(v, OP_MustBeInt, 1, brk);
- haveKey = 0;
- sqlite3VdbeAddOp(v, OP_NotExists, iCur, brk);
- pLevel->op = OP_Noop;
- }else if( pIdx!=0 && pLevel->score>0 && pLevel->score%4==0 ){
- /* Case 2: There is an index and all terms of the WHERE clause that
- ** refer to the index use the "==" or "IN" operators.
- */
- int start;
- int nColumn = (pLevel->score+4)/8;
- brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
-
- /* For each column of the index, find the term of the WHERE clause that
- ** constraints that column. If the WHERE clause term is X=expr, then
- ** evaluation expr and leave the result on the stack */
- for(j=0; j<nColumn; j++){
- for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
- Expr *pX = pTerm->p;
- if( pX==0 ) continue;
- if( pTerm->idxLeft==iCur
- && (pTerm->prereqRight & loopMask)==pTerm->prereqRight
- && pX->pLeft->iColumn==pIdx->aiColumn[j]
- ){
- char idxaff = pIdx->pTable->aCol[pX->pLeft->iColumn].affinity;
- if( sqlite3IndexAffinityOk(pX, idxaff) ){
- codeEqualityTerm(pParse, pTerm, brk, pLevel);
- break;
- }
- }
- }
- }
- pLevel->iMem = pParse->nMem++;
- cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
- buildIndexProbe(v, nColumn, brk, pIdx);
- sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 0);
-
- /* Generate code (1) to move to the first matching element of the table.
- ** Then generate code (2) that jumps to "brk" after the cursor is past
- ** the last matching element of the table. The code (1) is executed
- ** once to initialize the search, the code (2) is executed before each
- ** iteration of the scan to see if the scan has finished. */
- if( pLevel->bRev ){
- /* Scan in reverse order */
- sqlite3VdbeAddOp(v, OP_MoveLe, pLevel->iCur, brk);
- start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
- sqlite3VdbeAddOp(v, OP_IdxLT, pLevel->iCur, brk);
- pLevel->op = OP_Prev;
- }else{
- /* Scan in the forward order */
- sqlite3VdbeAddOp(v, OP_MoveGe, pLevel->iCur, brk);
- start = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
- sqlite3VdbeOp3(v, OP_IdxGE, pLevel->iCur, brk, "+", P3_STATIC);
- pLevel->op = OP_Next;
- }
- sqlite3VdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
- sqlite3VdbeAddOp(v, OP_IdxIsNull, nColumn, cont);
- sqlite3VdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
- if( i==pTabList->nSrc-1 && pushKey ){
- haveKey = 1;
- }else{
- sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
- haveKey = 0;
- }
- pLevel->p1 = pLevel->iCur;
- pLevel->p2 = start;
- }else if( i<ARRAYSIZE(iDirectLt) && (iDirectLt[i]>=0 || iDirectGt[i]>=0) ){
- /* Case 3: We have an inequality comparison against the ROWID field.
- */
- int testOp = OP_Noop;
- int start;
-
- brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
- cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
- if( iDirectGt[i]>=0 ){
- Expr *pX;
- k = iDirectGt[i];
- assert( k<nExpr );
- pTerm = &aExpr[k];
- pX = pTerm->p;
- assert( pX!=0 );
- assert( pTerm->idxLeft==iCur );
- sqlite3ExprCode(pParse, pX->pRight);
- sqlite3VdbeAddOp(v, OP_ForceInt, pX->op==TK_LT || pX->op==TK_GT, brk);
- sqlite3VdbeAddOp(v, OP_MoveGe, iCur, brk);
- disableTerm(pLevel, &pTerm->p);
- }else{
- sqlite3VdbeAddOp(v, OP_Rewind, iCur, brk);
- }
- if( iDirectLt[i]>=0 ){
- Expr *pX;
- k = iDirectLt[i];
- assert( k<nExpr );
- pTerm = &aExpr[k];
- pX = pTerm->p;
- assert( pX!=0 );
- assert( pTerm->idxLeft==iCur );
- sqlite3ExprCode(pParse, pX->pRight);
- pLevel->iMem = pParse->nMem++;
- sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
- if( pX->op==TK_LT || pX->op==TK_GT ){
- testOp = OP_Ge;
- }else{
- testOp = OP_Gt;
- }
- disableTerm(pLevel, &pTerm->p);
- }
- start = sqlite3VdbeCurrentAddr(v);
- pLevel->op = OP_Next;
- pLevel->p1 = iCur;
- pLevel->p2 = start;
- if( testOp!=OP_Noop ){
- sqlite3VdbeAddOp(v, OP_Recno, iCur, 0);
- sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
- sqlite3VdbeAddOp(v, testOp, 0, brk);
- }
- haveKey = 0;
- }else if( pIdx==0 ){
- /* Case 4: There is no usable index. We must do a complete
- ** scan of the entire database table.
- */
- int start;
-
- brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
- cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
- sqlite3VdbeAddOp(v, OP_Rewind, iCur, brk);
- start = sqlite3VdbeCurrentAddr(v);
- pLevel->op = OP_Next;
- pLevel->p1 = iCur;
- pLevel->p2 = start;
- haveKey = 0;
- }else{
- /* Case 5: The WHERE clause term that refers to the right-most
- ** column of the index is an inequality. For example, if
- ** the index is on (x,y,z) and the WHERE clause is of the
- ** form "x=5 AND y<10" then this case is used. Only the
- ** right-most column can be an inequality - the rest must
- ** use the "==" operator.
- **
- ** This case is also used when there are no WHERE clause
- ** constraints but an index is selected anyway, in order
- ** to force the output order to conform to an ORDER BY.
- */
- int score = pLevel->score;
- int nEqColumn = score/8;
- int start;
- int leFlag=0, geFlag=0;
- int testOp;
-
- /* Evaluate the equality constraints
- */
- for(j=0; j<nEqColumn; j++){
- int iIdxCol = pIdx->aiColumn[j];
- for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
- Expr *pX = pTerm->p;
- if( pX==0 ) continue;
- if( pTerm->idxLeft==iCur
- && pX->op==TK_EQ
- && (pTerm->prereqRight & loopMask)==pTerm->prereqRight
- && pX->pLeft->iColumn==iIdxCol
- ){
- sqlite3ExprCode(pParse, pX->pRight);
- disableTerm(pLevel, &pTerm->p);
- break;
- }
- }
- }
-
- /* Duplicate the equality term values because they will all be
- ** used twice: once to make the termination key and once to make the
- ** start key.
- */
- for(j=0; j<nEqColumn; j++){
- sqlite3VdbeAddOp(v, OP_Dup, nEqColumn-1, 0);
- }
-
- /* Labels for the beginning and end of the loop
- */
- cont = pLevel->cont = sqlite3VdbeMakeLabel(v);
- brk = pLevel->brk = sqlite3VdbeMakeLabel(v);
-
- /* Generate the termination key. This is the key value that
- ** will end the search. There is no termination key if there
- ** are no equality terms and no "X<..." term.
- **
- ** 2002-Dec-04: On a reverse-order scan, the so-called "termination"
- ** key computed here really ends up being the start key.
- */
- if( (score & 1)!=0 ){
- for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
- Expr *pX = pTerm->p;
- if( pX==0 ) continue;
- if( pTerm->idxLeft==iCur
- && (pX->op==TK_LT || pX->op==TK_LE)
- && (pTerm->prereqRight & loopMask)==pTerm->prereqRight
- && pX->pLeft->iColumn==pIdx->aiColumn[j]
- ){
- sqlite3ExprCode(pParse, pX->pRight);
- leFlag = pX->op==TK_LE;
- disableTerm(pLevel, &pTerm->p);
- break;
- }
- }
- testOp = OP_IdxGE;
- }else{
- testOp = nEqColumn>0 ? OP_IdxGE : OP_Noop;
- leFlag = 1;
- }
- if( testOp!=OP_Noop ){
- int nCol = nEqColumn + (score & 1);
- pLevel->iMem = pParse->nMem++;
- buildIndexProbe(v, nCol, brk, pIdx);
- if( pLevel->bRev ){
- int op = leFlag ? OP_MoveLe : OP_MoveLt;
- sqlite3VdbeAddOp(v, op, pLevel->iCur, brk);
- }else{
- sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
- }
- }else if( pLevel->bRev ){
- sqlite3VdbeAddOp(v, OP_Last, pLevel->iCur, brk);
- }
-
- /* Generate the start key. This is the key that defines the lower
- ** bound on the search. There is no start key if there are no
- ** equality terms and if there is no "X>..." term. In
- ** that case, generate a "Rewind" instruction in place of the
- ** start key search.
- **
- ** 2002-Dec-04: In the case of a reverse-order search, the so-called
- ** "start" key really ends up being used as the termination key.
- */
- if( (score & 2)!=0 ){
- for(pTerm=aExpr, k=0; k<nExpr; k++, pTerm++){
- Expr *pX = pTerm->p;
- if( pX==0 ) continue;
- if( pTerm->idxLeft==iCur
- && (pX->op==TK_GT || pX->op==TK_GE)
- && (pTerm->prereqRight & loopMask)==pTerm->prereqRight
- && pX->pLeft->iColumn==pIdx->aiColumn[j]
- ){
- sqlite3ExprCode(pParse, pX->pRight);
- geFlag = pX->op==TK_GE;
- disableTerm(pLevel, &pTerm->p);
- break;
- }
- }
- }else{
- geFlag = 1;
- }
- if( nEqColumn>0 || (score&2)!=0 ){
- int nCol = nEqColumn + ((score&2)!=0);
- buildIndexProbe(v, nCol, brk, pIdx);
- if( pLevel->bRev ){
- pLevel->iMem = pParse->nMem++;
- sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iMem, 1);
- testOp = OP_IdxLT;
- }else{
- int op = geFlag ? OP_MoveGe : OP_MoveGt;
- sqlite3VdbeAddOp(v, op, pLevel->iCur, brk);
- }
- }else if( pLevel->bRev ){
- testOp = OP_Noop;
- }else{
- sqlite3VdbeAddOp(v, OP_Rewind, pLevel->iCur, brk);
- }
-
- /* Generate the the top of the loop. If there is a termination
- ** key we have to test for that key and abort at the top of the
- ** loop.
- */
- start = sqlite3VdbeCurrentAddr(v);
- if( testOp!=OP_Noop ){
- sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iMem, 0);
- sqlite3VdbeAddOp(v, testOp, pLevel->iCur, brk);
- if( (leFlag && !pLevel->bRev) || (!geFlag && pLevel->bRev) ){
- sqlite3VdbeChangeP3(v, -1, "+", P3_STATIC);
- }
- }
- sqlite3VdbeAddOp(v, OP_RowKey, pLevel->iCur, 0);
- sqlite3VdbeAddOp(v, OP_IdxIsNull, nEqColumn + (score & 1), cont);
- sqlite3VdbeAddOp(v, OP_IdxRecno, pLevel->iCur, 0);
- if( i==pTabList->nSrc-1 && pushKey ){
- haveKey = 1;
- }else{
- sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
- haveKey = 0;
- }
-
- /* Record the instruction used to terminate the loop.
- */
- pLevel->op = pLevel->bRev ? OP_Prev : OP_Next;
- pLevel->p1 = pLevel->iCur;
- pLevel->p2 = start;
- }
- loopMask |= getMask(&maskSet, iCur);
-
- /* Insert code to test every subexpression that can be completely
- ** computed using the current set of tables.
- */
- for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
- if( pTerm->p==0 ) continue;
- if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
- if( pLevel->iLeftJoin && !ExprHasProperty(pTerm->p,EP_FromJoin) ){
- continue;
- }
- if( haveKey ){
- haveKey = 0;
- sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
- }
- sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
- pTerm->p = 0;
- }
- brk = cont;
-
- /* For a LEFT OUTER JOIN, generate code that will record the fact that
- ** at least one row of the right table has matched the left table.
- */
- if( pLevel->iLeftJoin ){
- pLevel->top = sqlite3VdbeCurrentAddr(v);
- sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
- sqlite3VdbeAddOp(v, OP_MemStore, pLevel->iLeftJoin, 1);
- VdbeComment((v, "# record LEFT JOIN hit"));
- for(pTerm=aExpr, j=0; j<nExpr; j++, pTerm++){
- if( pTerm->p==0 ) continue;
- if( (pTerm->prereqAll & loopMask)!=pTerm->prereqAll ) continue;
- if( haveKey ){
- /* Cannot happen. "haveKey" can only be true if pushKey is true
- ** an pushKey can only be true for DELETE and UPDATE and there are
- ** no outer joins with DELETE and UPDATE.
- */
- haveKey = 0;
- sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
- }
- sqlite3ExprIfFalse(pParse, pTerm->p, cont, 1);
- pTerm->p = 0;
- }
- }
- }
- pWInfo->iContinue = cont;
- if( pushKey && !haveKey ){
- sqlite3VdbeAddOp(v, OP_Recno, pTabList->a[0].iCursor, 0);
- }
- freeMaskSet(&maskSet);
- return pWInfo;
-}
-
-/*
-** Generate the end of the WHERE loop. See comments on
-** sqlite3WhereBegin() for additional information.
-*/
-void sqlite3WhereEnd(WhereInfo *pWInfo){
- Vdbe *v = pWInfo->pParse->pVdbe;
- int i;
- WhereLevel *pLevel;
- SrcList *pTabList = pWInfo->pTabList;
-
- for(i=pTabList->nSrc-1; i>=0; i--){
- pLevel = &pWInfo->a[i];
- sqlite3VdbeResolveLabel(v, pLevel->cont);
- if( pLevel->op!=OP_Noop ){
- sqlite3VdbeAddOp(v, pLevel->op, pLevel->p1, pLevel->p2);
- }
- sqlite3VdbeResolveLabel(v, pLevel->brk);
- if( pLevel->inOp!=OP_Noop ){
- sqlite3VdbeAddOp(v, pLevel->inOp, pLevel->inP1, pLevel->inP2);
- }
- if( pLevel->iLeftJoin ){
- int addr;
- addr = sqlite3VdbeAddOp(v, OP_MemLoad, pLevel->iLeftJoin, 0);
- sqlite3VdbeAddOp(v, OP_NotNull, 1, addr+4 + (pLevel->iCur>=0));
- sqlite3VdbeAddOp(v, OP_NullRow, pTabList->a[i].iCursor, 0);
- if( pLevel->iCur>=0 ){
- sqlite3VdbeAddOp(v, OP_NullRow, pLevel->iCur, 0);
- }
- sqlite3VdbeAddOp(v, OP_Goto, 0, pLevel->top);
- }
- }
- sqlite3VdbeResolveLabel(v, pWInfo->iBreak);
- for(i=0; i<pTabList->nSrc; i++){
- Table *pTab = pTabList->a[i].pTab;
- assert( pTab!=0 );
- if( pTab->isTransient || pTab->pSelect ) continue;
- pLevel = &pWInfo->a[i];
- sqlite3VdbeAddOp(v, OP_Close, pTabList->a[i].iCursor, 0);
- if( pLevel->pIdx!=0 ){
- sqlite3VdbeAddOp(v, OP_Close, pLevel->iCur, 0);
- }
- }
- sqliteFree(pWInfo);
- return;
-}