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:-) (CVS 52)

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FossilOrigin-Name: c02268bdf4c28edc2542ce0ca1ba24fd6b5058fa
This commit is contained in:
drh
2000-06-05 18:54:46 +00:00
parent 9bb61fe751
commit 19a775c249
14 changed files with 473 additions and 190 deletions
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158
src/select.c
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@@ -24,7 +24,7 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements.
**
** $Id: select.c,v 1.7 2000/06/05 16:01:39 drh Exp $
** $Id: select.c,v 1.8 2000/06/05 18:54:46 drh Exp $
*/
#include "sqliteInt.h"
@@ -71,11 +71,12 @@ void sqliteSelectDelete(Select *p){
/*
** Generate code for the given SELECT statement.
**
** If pDest==0 and iMem<0, then the results of the query are sent to
** the callback function. If pDest!=0 then the results are written to
** the single table specified. If pDest==0 and iMem>=0 then the result
** should be a single value which is then stored in memory location iMem
** of the virtual machine.
** If iDest<0 and iMem<0, then the results of the query are sent to
** the callback function. If iDest>=0 then the results are written to
** an open cursor with the index iDest. The calling function is
** responsible for having that cursor open. If iDest<0 and iMem>=0
** then the result should be a single value which is then stored in
** memory location iMem of the virtual machine.
**
** This routine returns the number of errors. If any errors are
** encountered, then an appropriate error message is left in
@@ -87,7 +88,7 @@ void sqliteSelectDelete(Select *p){
int sqliteSelect(
Parse *pParse, /* The parser context */
Select *p, /* The SELECT statement being coded. */
Table *pDest, /* Write results here, if not NULL */
int iDest, /* Write results to this cursor */
int iMem /* Save result in this memory location, if >=0 */
){
int i, j;
@@ -98,14 +99,14 @@ int sqliteSelect(
IdList *pTabList; /* List of tables to select from */
Expr *pWhere; /* The WHERE clause. May be NULL */
ExprList *pOrderBy; /* The ORDER BY clause. May be NULL */
int distinct; /* If true, only output distinct results */
int isDistinct; /* True if the DISTINCT keyword is present */
int distinct; /* Table to use for the distinct set */
pEList = p->pEList;
pTabList = p->pSrc;
pWhere = p->pWhere;
pOrderBy = p->pOrderBy;
distinct = p->isDistinct;
isDistinct = p->isDistinct;
/*
** Do not even attempt to generate any code if we have already seen
@@ -125,6 +126,13 @@ int sqliteSelect(
}
}
/* Allocate a temporary table to use for the DISTINCT set, if
** necessary.
*/
if( isDistinct ){
distinct = pParse->nTab++;
}
/* If the list of fields to retrieve is "*" then replace it with
** a list of all fields from all tables.
*/
@@ -133,13 +141,22 @@ int sqliteSelect(
Table *pTab = pTabList->a[i].pTab;
for(j=0; j<pTab->nCol; j++){
Expr *pExpr = sqliteExpr(TK_FIELD, 0, 0, 0);
pExpr->iTable = i;
pExpr->iTable = i + pParse->nTab;
pExpr->iField = j;
pEList = sqliteExprListAppend(pEList, pExpr, 0);
}
}
}
/* If writing to memory, only a single column may be output.
*/
if( iMem>=0 && pEList->nExpr>1 ){
sqliteSetString(&pParse->zErrMsg, "only a single result allowed for "
"a SELECT that is part of an expression", 0);
pParse->nErr++;
return 1;
}
/* Resolve the field names and do a semantics check on all the expressions.
*/
for(i=0; i<pEList->nExpr; i++){
@@ -180,17 +197,25 @@ int sqliteSelect(
}
}
/* ORDER BY is ignored if this is an aggregate query like count(*)
** since only one row will be returned.
/* ORDER BY is ignored if
**
** (1) this is an aggregate query like count(*)
** since only one row will be returned.
**
** (2) We are writing the result to another table, since the
** order will get scrambled again after inserting.
**
** (3) We are writing to a memory cell, since there is only
** one result.
*/
if( isAgg && pOrderBy ){
if( isAgg || iDest>=0 || iMem>=0 ){
pOrderBy = 0;
}
/* Turn off distinct if this is an aggregate
/* Turn off distinct if this is an aggregate or writing to memory.
*/
if( isAgg ){
distinct = 0;
if( isAgg || iMem>=0 ){
isDistinct = 0;
}
/* Begin generating code.
@@ -208,38 +233,42 @@ int sqliteSelect(
sqliteVdbeAddOp(v, OP_SortOpen, 0, 0, 0, 0);
}
/* Identify column names
/* Identify column names if we will be using a callback. This
** step is skipped if the output is going to a table or a memory cell.
*/
sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0, 0, 0);
for(i=0; i<pEList->nExpr; i++){
Expr *p;
if( pEList->a[i].zName ){
char *zName = pEList->a[i].zName;
int addr = sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
if( zName[0]=='\'' || zName[0]=='"' ){
sqliteVdbeDequoteP3(v, addr);
if( iDest<0 && iMem<0 ){
sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0, 0, 0);
for(i=0; i<pEList->nExpr; i++){
Expr *p;
if( pEList->a[i].zName ){
char *zName = pEList->a[i].zName;
int addr = sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
if( zName[0]=='\'' || zName[0]=='"' ){
sqliteVdbeDequoteP3(v, addr);
}
continue;
}
continue;
}
p = pEList->a[i].pExpr;
if( p->op!=TK_FIELD ){
char zName[30];
sprintf(zName, "field%d", i+1);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
}else{
if( pTabList->nId>1 ){
char *zName = 0;
Table *pTab = pTabList->a[p->iTable].pTab;
char *zTab;
zTab = pTabList->a[p->iTable].zAlias;
if( zTab==0 ) zTab = pTab->zName;
sqliteSetString(&zName, zTab, ".", pTab->aCol[p->iField].zName, 0);
p = pEList->a[i].pExpr;
if( p->op!=TK_FIELD ){
char zName[30];
sprintf(zName, "field%d", i+1);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
sqliteFree(zName);
}else{
Table *pTab = pTabList->a[0].pTab;
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, pTab->aCol[p->iField].zName, 0);
if( pTabList->nId>1 ){
char *zName = 0;
Table *pTab = pTabList->a[p->iTable].pTab;
char *zTab;
zTab = pTabList->a[p->iTable].zAlias;
if( zTab==0 ) zTab = pTab->zName;
sqliteSetString(&zName, zTab, ".", pTab->aCol[p->iField].zName, 0);
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
sqliteFree(zName);
}else{
Table *pTab = pTabList->a[0].pTab;
char *zName = pTab->aCol[p->iField].zName;
sqliteVdbeAddOp(v, OP_ColumnName, i, 0, zName, 0);
}
}
}
}
@@ -263,10 +292,16 @@ int sqliteSelect(
}
}
/* Initialize the memory cell to NULL
*/
if( iMem>=0 ){
sqliteVdbeAddOp(v, OP_Null, 0, 0, 0, 0);
sqliteVdbeAddOp(v, OP_MemStore, iMem, 0, 0, 0);
}
/* Begin the database scan
*/
if( distinct ){
distinct = pTabList->nId*2+1;
if( isDistinct ){
sqliteVdbeAddOp(v, OP_Open, distinct, 1, 0, 0);
}
pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0);
@@ -283,13 +318,13 @@ int sqliteSelect(
/* If the current result is not distinct, script the remainder
** of this processing.
*/
if( distinct ){
int isDistinct = sqliteVdbeMakeLabel(v);
if( isDistinct ){
int lbl = sqliteVdbeMakeLabel(v);
sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1, 0, 0);
sqliteVdbeAddOp(v, OP_Distinct, distinct, isDistinct, 0, 0);
sqliteVdbeAddOp(v, OP_Distinct, distinct, lbl, 0, 0);
sqliteVdbeAddOp(v, OP_Pop, pEList->nExpr+1, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, pWInfo->iContinue, 0, 0);
sqliteVdbeAddOp(v, OP_String, 0, 0, "", isDistinct);
sqliteVdbeAddOp(v, OP_String, 0, 0, "", lbl);
sqliteVdbeAddOp(v, OP_Put, distinct, 0, 0, 0);
}
@@ -330,6 +365,14 @@ int sqliteSelect(
}
sqliteVdbeAddOp(v, op, p1, 0, 0, 0);
}
}else if( iDest>=0 ){
sqliteVdbeAddOp(v, OP_MakeRecord, pEList->nExpr, 0, 0, 0);
sqliteVdbeAddOp(v, OP_New, iDest, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Pull, 1, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Put, iDest, 0, 0, 0);
}else if( iMem>=0 ){
sqliteVdbeAddOp(v, OP_MemStore, iMem, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, pWInfo->iBreak, 0, 0);
}else{
sqliteVdbeAddOp(v, OP_Callback, pEList->nExpr, 0, 0, 0);
}
@@ -348,14 +391,23 @@ int sqliteSelect(
addr = sqliteVdbeAddOp(v, OP_SortNext, 0, end, 0, 0);
sqliteVdbeAddOp(v, OP_SortCallback, pEList->nExpr, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Goto, 0, addr, 0, 0);
sqliteVdbeAddOp(v, OP_Noop, 0, 0, 0, end);
sqliteVdbeAddOp(v, OP_SortClose, 0, 0, 0, end);
}
/* If this is an aggregate, then we need to invoke the callback
** exactly once.
*/
if( isAgg ){
sqliteVdbeAddOp(v, OP_Callback, pEList->nExpr, 0, 0, 0);
if( iDest>=0 ){
sqliteVdbeAddOp(v, OP_MakeRecord, pEList->nExpr, 0, 0, 0);
sqliteVdbeAddOp(v, OP_New, iDest, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Pull, 1, 0, 0, 0);
sqliteVdbeAddOp(v, OP_Put, iDest, 0, 0, 0);
}else if( iMem>=0 ){
sqliteVdbeAddOp(v, OP_MemStore, iMem, 0, 0, 0);
}else{
sqliteVdbeAddOp(v, OP_Callback, pEList->nExpr, 0, 0, 0);
}
}
return 0;
}