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4844 lines (4573 loc) · 171 KB
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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 file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
*/
#include "sqliteInt.h"
/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
*/
static void clearSelect(sqlite3 *db, Select *p){
sqlite3ExprListDelete(db, p->pEList);
sqlite3SrcListDelete(db, p->pSrc);
sqlite3ExprDelete(db, p->pWhere);
sqlite3ExprListDelete(db, p->pGroupBy);
sqlite3ExprDelete(db, p->pHaving);
sqlite3ExprListDelete(db, p->pOrderBy);
sqlite3SelectDelete(db, p->pPrior);
sqlite3ExprDelete(db, p->pLimit);
sqlite3ExprDelete(db, p->pOffset);
}
/*
** Initialize a SelectDest structure.
*/
void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
pDest->eDest = (u8)eDest;
pDest->iSDParm = iParm;
pDest->affSdst = 0;
pDest->iSdst = 0;
pDest->nSdst = 0;
}
/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/
Select *sqlite3SelectNew(
Parse *pParse, /* Parsing context */
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 */
u16 selFlags, /* Flag parameters, such as SF_Distinct */
Expr *pLimit, /* LIMIT value. NULL means not used */
Expr *pOffset /* OFFSET value. NULL means no offset */
){
Select *pNew;
Select standin;
sqlite3 *db = pParse->db;
pNew = sqlite3DbMallocZero(db, sizeof(*pNew) );
assert( db->mallocFailed || !pOffset || pLimit ); /* OFFSET implies LIMIT */
if( pNew==0 ){
assert( db->mallocFailed );
pNew = &standin;
memset(pNew, 0, sizeof(*pNew));
}
if( pEList==0 ){
pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db,TK_ALL,0));
}
pNew->pEList = pEList;
if( pSrc==0 ) pSrc = sqlite3DbMallocZero(db, sizeof(*pSrc));
pNew->pSrc = pSrc;
pNew->pWhere = pWhere;
pNew->pGroupBy = pGroupBy;
pNew->pHaving = pHaving;
pNew->pOrderBy = pOrderBy;
pNew->selFlags = selFlags;
pNew->op = TK_SELECT;
pNew->pLimit = pLimit;
pNew->pOffset = pOffset;
assert( pOffset==0 || pLimit!=0 );
pNew->addrOpenEphm[0] = -1;
pNew->addrOpenEphm[1] = -1;
pNew->addrOpenEphm[2] = -1;
if( db->mallocFailed ) {
clearSelect(db, pNew);
if( pNew!=&standin ) sqlite3DbFree(db, pNew);
pNew = 0;
}else{
assert( pNew->pSrc!=0 || pParse->nErr>0 );
}
assert( pNew!=&standin );
return pNew;
}
/*
** Delete the given Select structure and all of its substructures.
*/
void sqlite3SelectDelete(sqlite3 *db, Select *p){
if( p ){
clearSelect(db, p);
sqlite3DbFree(db, p);
}
}
/*
** Given 1 to 3 identifiers preceding 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_CROSS
** 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;
/* 0123456789 123456789 123456789 123 */
static const char zKeyText[] = "naturaleftouterightfullinnercross";
static const struct {
u8 i; /* Beginning of keyword text in zKeyText[] */
u8 nChar; /* Length of the keyword in characters */
u8 code; /* Join type mask */
} aKeyword[] = {
/* natural */ { 0, 7, JT_NATURAL },
/* left */ { 6, 4, JT_LEFT|JT_OUTER },
/* outer */ { 10, 5, JT_OUTER },
/* right */ { 14, 5, JT_RIGHT|JT_OUTER },
/* full */ { 19, 4, JT_LEFT|JT_RIGHT|JT_OUTER },
/* inner */ { 23, 5, JT_INNER },
/* cross */ { 28, 5, JT_INNER|JT_CROSS },
};
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<ArraySize(aKeyword); j++){
if( p->n==aKeyword[j].nChar
&& sqlite3StrNICmp((char*)p->z, &zKeyText[aKeyword[j].i], p->n)==0 ){
jointype |= aKeyword[j].code;
break;
}
}
testcase( j==0 || j==1 || j==2 || j==3 || j==4 || j==5 || j==6 );
if( j>=ArraySize(aKeyword) ){
jointype |= JT_ERROR;
break;
}
}
if(
(jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
(jointype & JT_ERROR)!=0
){
const char *zSp = " ";
assert( pB!=0 );
if( pC==0 ){ zSp++; }
sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
"%T %T%s%T", pA, pB, zSp, pC);
jointype = JT_INNER;
}else if( (jointype & JT_OUTER)!=0
&& (jointype & (JT_LEFT|JT_RIGHT))!=JT_LEFT ){
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;
}
/*
** Search the first N tables in pSrc, from left to right, looking for a
** table that has a column named zCol.
**
** When found, set *piTab and *piCol to the table index and column index
** of the matching column and return TRUE.
**
** If not found, return FALSE.
*/
static int tableAndColumnIndex(
SrcList *pSrc, /* Array of tables to search */
int N, /* Number of tables in pSrc->a[] to search */
const char *zCol, /* Name of the column we are looking for */
int *piTab, /* Write index of pSrc->a[] here */
int *piCol /* Write index of pSrc->a[*piTab].pTab->aCol[] here */
){
int i; /* For looping over tables in pSrc */
int iCol; /* Index of column matching zCol */
assert( (piTab==0)==(piCol==0) ); /* Both or neither are NULL */
for(i=0; i<N; i++){
iCol = columnIndex(pSrc->a[i].pTab, zCol);
if( iCol>=0 ){
if( piTab ){
*piTab = i;
*piCol = iCol;
}
return 1;
}
}
return 0;
}
/*
** This function is used to add terms implied by JOIN syntax to the
** WHERE clause expression of a SELECT statement. The new term, which
** is ANDed with the existing WHERE clause, is of the form:
**
** (tab1.col1 = tab2.col2)
**
** where tab1 is the iSrc'th table in SrcList pSrc and tab2 is the
** (iSrc+1)'th. Column col1 is column iColLeft of tab1, and col2 is
** column iColRight of tab2.
*/
static void addWhereTerm(
Parse *pParse, /* Parsing context */
SrcList *pSrc, /* List of tables in FROM clause */
int iLeft, /* Index of first table to join in pSrc */
int iColLeft, /* Index of column in first table */
int iRight, /* Index of second table in pSrc */
int iColRight, /* Index of column in second table */
int isOuterJoin, /* True if this is an OUTER join */
Expr **ppWhere /* IN/OUT: The WHERE clause to add to */
){
sqlite3 *db = pParse->db;
Expr *pE1;
Expr *pE2;
Expr *pEq;
assert( iLeft<iRight );
assert( pSrc->nSrc>iRight );
assert( pSrc->a[iLeft].pTab );
assert( pSrc->a[iRight].pTab );
pE1 = sqlite3CreateColumnExpr(db, pSrc, iLeft, iColLeft);
pE2 = sqlite3CreateColumnExpr(db, pSrc, iRight, iColRight);
pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2, 0);
if( pEq && isOuterJoin ){
ExprSetProperty(pEq, EP_FromJoin);
assert( !ExprHasAnyProperty(pEq, EP_TokenOnly|EP_Reduced) );
ExprSetIrreducible(pEq);
pEq->iRightJoinTable = (i16)pE2->iTable;
}
*ppWhere = sqlite3ExprAnd(db, *ppWhere, pEq);
}
/*
** Set the EP_FromJoin property on all terms of the given expression.
** And set the Expr.iRightJoinTable to iTable for every term in the
** 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.
**
** The Expr.iRightJoinTable tells the WHERE clause processing that the
** expression depends on table iRightJoinTable even if that table is not
** explicitly mentioned in the expression. That information is needed
** for cases like this:
**
** SELECT * FROM t1 LEFT JOIN t2 ON t1.a=t2.b AND t1.x=5
**
** The where clause needs to defer the handling of the t1.x=5
** term until after the t2 loop of the join. In that way, a
** NULL t2 row will be inserted whenever t1.x!=5. If we do not
** defer the handling of t1.x=5, it will be processed immediately
** after the t1 loop and rows with t1.x!=5 will never appear in
** the output, which is incorrect.
*/
static void setJoinExpr(Expr *p, int iTable){
while( p ){
ExprSetProperty(p, EP_FromJoin);
assert( !ExprHasAnyProperty(p, EP_TokenOnly|EP_Reduced) );
ExprSetIrreducible(p);
p->iRightJoinTable = (i16)iTable;
setJoinExpr(p->pLeft, iTable);
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;
int isOuter;
if( NEVER(pLeftTab==0 || pRightTab==0) ) continue;
isOuter = (pRight->jointype & JT_OUTER)!=0;
/* When the NATURAL keyword is present, add WHERE clause terms for
** every column that the two tables have in common.
*/
if( pRight->jointype & JT_NATURAL ){
if( pRight->pOn || pRight->pUsing ){
sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
"an ON or USING clause", 0);
return 1;
}
for(j=0; j<pRightTab->nCol; j++){
char *zName; /* Name of column in the right table */
int iLeft; /* Matching left table */
int iLeftCol; /* Matching column in the left table */
zName = pRightTab->aCol[j].zName;
if( tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol) ){
addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, j,
isOuter, &p->pWhere);
}
}
}
/* Disallow both ON and USING clauses in the same join
*/
if( pRight->pOn && pRight->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( pRight->pOn ){
if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
pRight->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( pRight->pUsing ){
IdList *pList = pRight->pUsing;
for(j=0; j<pList->nId; j++){
char *zName; /* Name of the term in the USING clause */
int iLeft; /* Table on the left with matching column name */
int iLeftCol; /* Column number of matching column on the left */
int iRightCol; /* Column number of matching column on the right */
zName = pList->a[j].zName;
iRightCol = columnIndex(pRightTab, zName);
if( iRightCol<0
|| !tableAndColumnIndex(pSrc, i+1, zName, &iLeft, &iLeftCol)
){
sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
"not present in both tables", zName);
return 1;
}
addWhereTerm(pParse, pSrc, iLeft, iLeftCol, i+1, iRightCol,
isOuter, &p->pWhere);
}
}
}
return 0;
}
/*
** Insert code into "v" that will push the record on the top of the
** stack into the sorter.
*/
static void pushOntoSorter(
Parse *pParse, /* Parser context */
ExprList *pOrderBy, /* The ORDER BY clause */
Select *pSelect, /* The whole SELECT statement */
int regData /* Register holding data to be sorted */
){
Vdbe *v = pParse->pVdbe;
int nExpr = pOrderBy->nExpr;
int regBase = sqlite3GetTempRange(pParse, nExpr+2);
int regRecord = sqlite3GetTempReg(pParse);
int op;
sqlite3ExprCacheClear(pParse);
sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
if( pSelect->selFlags & SF_UseSorter ){
op = OP_SorterInsert;
}else{
op = OP_IdxInsert;
}
sqlite3VdbeAddOp2(v, op, pOrderBy->iECursor, regRecord);
sqlite3ReleaseTempReg(pParse, regRecord);
sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
if( pSelect->iLimit ){
int addr1, addr2;
int iLimit;
if( pSelect->iOffset ){
iLimit = pSelect->iOffset+1;
}else{
iLimit = pSelect->iLimit;
}
addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
sqlite3VdbeJumpHere(v, addr1);
sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
sqlite3VdbeJumpHere(v, addr2);
}
}
/*
** Add code to implement the OFFSET
*/
static void codeOffset(
Vdbe *v, /* Generate code into this VM */
Select *p, /* The SELECT statement being coded */
int iContinue /* Jump here to skip the current record */
){
if( p->iOffset && iContinue!=0 ){
int addr;
sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
VdbeComment((v, "skip OFFSET records"));
sqlite3VdbeJumpHere(v, addr);
}
}
/*
** Add code that will check to make sure the N registers starting at iMem
** form a distinct entry. iTab is a sorting index that holds previously
** seen combinations of the N values. A new entry is made in iTab
** if the current N values are new.
**
** A jump to addrRepeat is made and the N+1 values are popped from the
** stack if the top N elements are not distinct.
*/
static void codeDistinct(
Parse *pParse, /* Parsing and code generating context */
int iTab, /* A sorting index used to test for distinctness */
int addrRepeat, /* Jump to here if not distinct */
int N, /* Number of elements */
int iMem /* First element */
){
Vdbe *v;
int r1;
v = pParse->pVdbe;
r1 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp4Int(v, OP_Found, iTab, addrRepeat, iMem, N);
sqlite3VdbeAddOp3(v, OP_MakeRecord, iMem, N, r1);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iTab, r1);
sqlite3ReleaseTempReg(pParse, r1);
}
#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate an error message when a SELECT is used within a subexpression
** (example: "a IN (SELECT * FROM table)") but it has more than 1 result
** column. We do this in a subroutine because the error used to occur
** in multiple places. (The error only occurs in one place now, but we
** retain the subroutine to minimize code disruption.)
*/
static int checkForMultiColumnSelectError(
Parse *pParse, /* Parse context. */
SelectDest *pDest, /* Destination of SELECT results */
int nExpr /* Number of result columns returned by SELECT */
){
int eDest = pDest->eDest;
if( nExpr>1 && (eDest==SRT_Mem || eDest==SRT_Set) ){
sqlite3ErrorMsg(pParse, "only a single result allowed for "
"a SELECT that is part of an expression");
return 1;
}else{
return 0;
}
}
#endif
/*
** An instance of the following object is used to record information about
** how to process the DISTINCT keyword, to simplify passing that information
** into the selectInnerLoop() routine.
*/
typedef struct DistinctCtx DistinctCtx;
struct DistinctCtx {
u8 isTnct; /* True if the DISTINCT keyword is present */
u8 eTnctType; /* One of the WHERE_DISTINCT_* operators */
int tabTnct; /* Ephemeral table used for DISTINCT processing */
int addrTnct; /* Address of OP_OpenEphemeral opcode for tabTnct */
};
/*
** 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 void 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 */
DistinctCtx *pDistinct, /* If not NULL, info on how to process DISTINCT */
SelectDest *pDest, /* How to dispose of the results */
int iContinue, /* Jump here to continue with next row */
int iBreak /* Jump here to break out of the inner loop */
){
Vdbe *v = pParse->pVdbe;
int i;
int hasDistinct; /* True if the DISTINCT keyword is present */
int regResult; /* Start of memory holding result set */
int eDest = pDest->eDest; /* How to dispose of results */
int iParm = pDest->iSDParm; /* First argument to disposal method */
int nResultCol; /* Number of result columns */
assert( v );
if( NEVER(v==0) ) return;
assert( pEList!=0 );
hasDistinct = pDistinct ? pDistinct->eTnctType : WHERE_DISTINCT_NOOP;
if( pOrderBy==0 && !hasDistinct ){
codeOffset(v, p, iContinue);
}
/* Pull the requested columns.
*/
if( nColumn>0 ){
nResultCol = nColumn;
}else{
nResultCol = pEList->nExpr;
}
if( pDest->iSdst==0 ){
pDest->iSdst = pParse->nMem+1;
pDest->nSdst = nResultCol;
pParse->nMem += nResultCol;
}else{
assert( pDest->nSdst==nResultCol );
}
regResult = pDest->iSdst;
if( nColumn>0 ){
for(i=0; i<nColumn; i++){
sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
}
}else if( eDest!=SRT_Exists ){
/* If the destination is an EXISTS(...) expression, the actual
** values returned by the SELECT are not required.
*/
sqlite3ExprCacheClear(pParse);
sqlite3ExprCodeExprList(pParse, pEList, regResult, eDest==SRT_Output);
}
nColumn = nResultCol;
/* 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 ){
assert( pEList!=0 );
assert( pEList->nExpr==nColumn );
switch( pDistinct->eTnctType ){
case WHERE_DISTINCT_ORDERED: {
VdbeOp *pOp; /* No longer required OpenEphemeral instr. */
int iJump; /* Jump destination */
int regPrev; /* Previous row content */
/* Allocate space for the previous row */
regPrev = pParse->nMem+1;
pParse->nMem += nColumn;
/* Change the OP_OpenEphemeral coded earlier to an OP_Null
** sets the MEM_Cleared bit on the first register of the
** previous value. This will cause the OP_Ne below to always
** fail on the first iteration of the loop even if the first
** row is all NULLs.
*/
sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct);
pOp = sqlite3VdbeGetOp(v, pDistinct->addrTnct);
pOp->opcode = OP_Null;
pOp->p1 = 1;
pOp->p2 = regPrev;
iJump = sqlite3VdbeCurrentAddr(v) + nColumn;
for(i=0; i<nColumn; i++){
CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr);
if( i<nColumn-1 ){
sqlite3VdbeAddOp3(v, OP_Ne, regResult+i, iJump, regPrev+i);
}else{
sqlite3VdbeAddOp3(v, OP_Eq, regResult+i, iContinue, regPrev+i);
}
sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
}
assert( sqlite3VdbeCurrentAddr(v)==iJump );
sqlite3VdbeAddOp3(v, OP_Copy, regResult, regPrev, nColumn-1);
break;
}
case WHERE_DISTINCT_UNIQUE: {
sqlite3VdbeChangeToNoop(v, pDistinct->addrTnct);
break;
}
default: {
assert( pDistinct->eTnctType==WHERE_DISTINCT_UNORDERED );
codeDistinct(pParse, pDistinct->tabTnct, iContinue, nColumn, regResult);
break;
}
}
if( pOrderBy==0 ){
codeOffset(v, p, iContinue);
}
}
switch( eDest ){
/* In this mode, write each query result to the key of the temporary
** table iParm.
*/
#ifndef SQLITE_OMIT_COMPOUND_SELECT
case SRT_Union: {
int r1;
r1 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
sqlite3ReleaseTempReg(pParse, r1);
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: {
sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nColumn);
break;
}
#endif
/* Store the result as data using a unique key.
*/
case SRT_Table:
case SRT_EphemTab: {
int r1 = sqlite3GetTempReg(pParse);
testcase( eDest==SRT_Table );
testcase( eDest==SRT_EphemTab );
sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
if( pOrderBy ){
pushOntoSorter(pParse, pOrderBy, p, r1);
}else{
int r2 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
sqlite3ReleaseTempReg(pParse, r2);
}
sqlite3ReleaseTempReg(pParse, r1);
break;
}
#ifndef SQLITE_OMIT_SUBQUERY
/* 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: {
assert( nColumn==1 );
pDest->affSdst =
sqlite3CompareAffinity(pEList->a[0].pExpr, pDest->affSdst);
if( pOrderBy ){
/* At first glance you would think we could optimize out the
** ORDER BY in this case since the order of entries in the set
** does not matter. But there might be a LIMIT clause, in which
** case the order does matter */
pushOntoSorter(pParse, pOrderBy, p, regResult);
}else{
int r1 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult,1,r1, &pDest->affSdst, 1);
sqlite3ExprCacheAffinityChange(pParse, regResult, 1);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
sqlite3ReleaseTempReg(pParse, r1);
}
break;
}
/* If any row exist in the result set, record that fact and abort.
*/
case SRT_Exists: {
sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
/* The LIMIT clause will terminate the loop for us */
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, pOrderBy, p, regResult);
}else{
sqlite3ExprCodeMove(pParse, regResult, iParm, 1);
/* The LIMIT clause will jump out of the loop for us */
}
break;
}
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */
/* Send the data to the callback function or to a subroutine. In the
** case of a subroutine, the subroutine itself is responsible for
** popping the data from the stack.
*/
case SRT_Coroutine:
case SRT_Output: {
testcase( eDest==SRT_Coroutine );
testcase( eDest==SRT_Output );
if( pOrderBy ){
int r1 = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
pushOntoSorter(pParse, pOrderBy, p, r1);
sqlite3ReleaseTempReg(pParse, r1);
}else if( eDest==SRT_Coroutine ){
sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
}else{
sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
}
break;
}
#if !defined(SQLITE_OMIT_TRIGGER)
/* 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 );
break;
}
#endif
}
/* Jump to the end of the loop if the LIMIT is reached. Except, if
** there is a sorter, in which case the sorter has already limited
** the output for us.
*/
if( pOrderBy==0 && p->iLimit ){
sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
}
}
/*
** Allocate a KeyInfo object sufficient for an index of N columns.
**
** Actually, always allocate one extra column for the rowid at the end
** of the index. So the KeyInfo returned will have space sufficient for
** N+1 columns.
*/
KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N){
KeyInfo *p = sqlite3DbMallocZero(db,
sizeof(KeyInfo) + (N+1)*(sizeof(CollSeq*)+1));
if( p ){
p->aSortOrder = (u8*)&p->aColl[N+1];
p->nField = (u16)N;
p->enc = ENC(db);
p->db = db;
}
return p;
}
/*
** Given an expression list, generate a KeyInfo structure that records
** the collating sequence for each expression in that expression list.
**
** If the ExprList is an ORDER BY or GROUP BY clause then the resulting
** KeyInfo structure is appropriate for initializing a virtual index to
** implement that clause. If the ExprList is the result set of a SELECT
** then the KeyInfo structure is appropriate for initializing a virtual
** index to implement a DISTINCT test.
**
** Space to hold the KeyInfo structure is obtain from malloc. The calling
** function is responsible for seeing that this structure is eventually
** freed. Add the KeyInfo structure to the P4 field of an opcode using
** P4_KEYINFO_HANDOFF is the usual way of dealing with this.
*/
static KeyInfo *keyInfoFromExprList(Parse *pParse, ExprList *pList){
int nExpr;
KeyInfo *pInfo;
struct ExprList_item *pItem;
sqlite3 *db = pParse->db;
int i;
nExpr = pList->nExpr;
pInfo = sqlite3KeyInfoAlloc(db, nExpr);
if( pInfo ){
for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
CollSeq *pColl;
pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
if( !pColl ) pColl = db->pDfltColl;
pInfo->aColl[i] = pColl;
pInfo->aSortOrder[i] = pItem->sortOrder;
}
}
return pInfo;
}
#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** 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;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */
#ifndef SQLITE_OMIT_EXPLAIN
/*
** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
** is a no-op. Otherwise, it adds a single row of output to the EQP result,
** where the caption is of the form:
**
** "USE TEMP B-TREE FOR xxx"
**
** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
** is determined by the zUsage argument.
*/
static void explainTempTable(Parse *pParse, const char *zUsage){
if( pParse->explain==2 ){
Vdbe *v = pParse->pVdbe;
char *zMsg = sqlite3MPrintf(pParse->db, "USE TEMP B-TREE FOR %s", zUsage);
sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
}
}
/*
** Assign expression b to lvalue a. A second, no-op, version of this macro
** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
** in sqlite3Select() to assign values to structure member variables that
** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
** code with #ifndef directives.
*/
# define explainSetInteger(a, b) a = b
#else
/* No-op versions of the explainXXX() functions and macros. */
# define explainTempTable(y,z)
# define explainSetInteger(y,z)
#endif
#if !defined(SQLITE_OMIT_EXPLAIN) && !defined(SQLITE_OMIT_COMPOUND_SELECT)
/*
** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
** is a no-op. Otherwise, it adds a single row of output to the EQP result,
** where the caption is of one of the two forms:
**
** "COMPOSITE SUBQUERIES iSub1 and iSub2 (op)"
** "COMPOSITE SUBQUERIES iSub1 and iSub2 USING TEMP B-TREE (op)"
**
** where iSub1 and iSub2 are the integers passed as the corresponding
** function parameters, and op is the text representation of the parameter
** of the same name. The parameter "op" must be one of TK_UNION, TK_EXCEPT,
** TK_INTERSECT or TK_ALL. The first form is used if argument bUseTmp is
** false, or the second form if it is true.
*/
static void explainComposite(
Parse *pParse, /* Parse context */
int op, /* One of TK_UNION, TK_EXCEPT etc. */
int iSub1, /* Subquery id 1 */
int iSub2, /* Subquery id 2 */
int bUseTmp /* True if a temp table was used */
){
assert( op==TK_UNION || op==TK_EXCEPT || op==TK_INTERSECT || op==TK_ALL );
if( pParse->explain==2 ){
Vdbe *v = pParse->pVdbe;
char *zMsg = sqlite3MPrintf(
pParse->db, "COMPOUND SUBQUERIES %d AND %d %s(%s)", iSub1, iSub2,
bUseTmp?"USING TEMP B-TREE ":"", selectOpName(op)
);
sqlite3VdbeAddOp4(v, OP_Explain, pParse->iSelectId, 0, 0, zMsg, P4_DYNAMIC);
}
}
#else
/* No-op versions of the explainXXX() functions and macros. */
# define explainComposite(v,w,x,y,z)
#endif
/*
** 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, /* Parsing context */
Select *p, /* The SELECT statement */
Vdbe *v, /* Generate code into this VDBE */
int nColumn, /* Number of columns of data */
SelectDest *pDest /* Write the sorted results here */
){
int addrBreak = sqlite3VdbeMakeLabel(v); /* Jump here to exit loop */
int addrContinue = sqlite3VdbeMakeLabel(v); /* Jump here for next cycle */
int addr;
int iTab;
int pseudoTab = 0;
ExprList *pOrderBy = p->pOrderBy;
int eDest = pDest->eDest;
int iParm = pDest->iSDParm;
int regRow;
int regRowid;
iTab = pOrderBy->iECursor;
regRow = sqlite3GetTempReg(pParse);
if( eDest==SRT_Output || eDest==SRT_Coroutine ){
pseudoTab = pParse->nTab++;
sqlite3VdbeAddOp3(v, OP_OpenPseudo, pseudoTab, regRow, nColumn);
regRowid = 0;
}else{
regRowid = sqlite3GetTempReg(pParse);
}
if( p->selFlags & SF_UseSorter ){
int regSortOut = ++pParse->nMem;
int ptab2 = pParse->nTab++;
sqlite3VdbeAddOp3(v, OP_OpenPseudo, ptab2, regSortOut, pOrderBy->nExpr+2);
addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
codeOffset(v, p, addrContinue);
sqlite3VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
sqlite3VdbeAddOp3(v, OP_Column, ptab2, pOrderBy->nExpr+1, regRow);
sqlite3VdbeChangeP5(v, OPFLAG_CLEARCACHE);
}else{
addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
codeOffset(v, p, addrContinue);
sqlite3VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr+1, regRow);
}
switch( eDest ){
case SRT_Table:
case SRT_EphemTab: {
testcase( eDest==SRT_Table );
testcase( eDest==SRT_EphemTab );