database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-14 00:22:38 +03:00
Code Activity

separate Select structure (CVS 51)

Browse Source 
FossilOrigin-Name: ce45dea902f9010a1c2c9ba3550dd789e7c15fcd
This commit is contained in:
drh
2000-06-05 16:01:39 +00:00
parent d1dedb86bf
commit 9bb61fe751
8 changed files with 163 additions and 73 deletions
Download Patch File Download Diff File Expand all files Collapse all files

122
src/select.c
View File

@@ -24,28 +24,94 @@
** This file contains C code routines that are called by the parser
** to handle SELECT statements.
**
** $Id: select.c,v 1.6 2000/06/04 12:58:38 drh Exp $
** $Id: select.c,v 1.7 2000/06/05 16:01:39 drh Exp $
*/
#include "sqliteInt.h"
/*
** Process a SELECT statement.
** Allocate a new Select structure and return a pointer to that
** structure.
*/
void sqliteSelect(
Select *sqliteSelectNew(
ExprList *pEList,
IdList *pSrc,
Expr *pWhere,
ExprList *pGroupBy,
Expr *pHaving,
ExprList *pOrderBy,
int isDistinct
){
Select *pNew;
pNew = sqliteMalloc( sizeof(*pNew) );
if( pNew==0 ) return 0;
pNew->pEList = pEList;
pNew->pSrc = pSrc;
pNew->pWhere = pWhere;
pNew->pGroupBy = pGroupBy;
pNew->pHaving = pHaving;
pNew->pOrderBy = pOrderBy;
pNew->isDistinct = isDistinct;
return pNew;
}
/*
** Delete the given Select structure and all of its substructures.
*/
void sqliteSelectDelete(Select *p){
sqliteExprListDelete(p->pEList);
sqliteIdListDelete(p->pSrc);
sqliteExprDelete(p->pWhere);
sqliteExprListDelete(p->pGroupBy);
sqliteExprDelete(p->pHaving);
sqliteExprListDelete(p->pOrderBy);
sqliteFree(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.
**
** 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.
*/
int sqliteSelect(
Parse *pParse, /* The parser context */
ExprList *pEList, /* List of fields to extract. NULL means "*" */
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 */
Select *p, /* The SELECT statement being coded. */
Table *pDest, /* Write results here, if not NULL */
int iMem /* Save result in this memory location, if >=0 */
){
int i, j;
WhereInfo *pWInfo;
Vdbe *v;
int isAgg = 0; /* True for select lists like "count(*)" */
ExprList *pEList; /* List of fields to extract. NULL means "*" */
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 */
if( pParse->nErr>0 ) goto select_cleanup;
pEList = p->pEList;
pTabList = p->pSrc;
pWhere = p->pWhere;
pOrderBy = p->pOrderBy;
distinct = p->isDistinct;
/*
** Do not even attempt to generate any code if we have already seen
** errors before this routine starts.
*/
if( pParse->nErr>0 ) return 0;
/* Look up every table in the table list.
*/
@@ -55,7 +121,7 @@ void sqliteSelect(
sqliteSetString(&pParse->zErrMsg, "no such table: ",
pTabList->a[i].zName, 0);
pParse->nErr++;
goto select_cleanup;
return 1;
}
}
@@ -78,10 +144,10 @@ void sqliteSelect(
*/
for(i=0; i<pEList->nExpr; i++){
if( sqliteExprResolveIds(pParse, pTabList, pEList->a[i].pExpr) ){
goto select_cleanup;
return 1;
}
if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &pEList->a[i].isAgg) ){
goto select_cleanup;
return 1;
}
}
if( pEList->nExpr>0 ){
@@ -91,25 +157,25 @@ void sqliteSelect(
sqliteSetString(&pParse->zErrMsg, "some selected items are aggregates "
"and others are not", 0);
pParse->nErr++;
goto select_cleanup;
return 1;
}
}
}
if( pWhere ){
if( sqliteExprResolveIds(pParse, pTabList, pWhere) ){
goto select_cleanup;
return 1;
}
if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
goto select_cleanup;
return 1;
}
}
if( pOrderBy ){
for(i=0; i<pOrderBy->nExpr; i++){
if( sqliteExprResolveIds(pParse, pTabList, pOrderBy->a[i].pExpr) ){
goto select_cleanup;
return 1;
}
if( sqliteExprCheck(pParse, pOrderBy->a[i].pExpr, 0, 0) ){
goto select_cleanup;
return 1;
}
}
}
@@ -118,7 +184,6 @@ void sqliteSelect(
** since only one row will be returned.
*/
if( isAgg && pOrderBy ){
sqliteExprListDelete(pOrderBy);
pOrderBy = 0;
}
@@ -134,7 +199,11 @@ void sqliteSelect(
if( v==0 ){
v = pParse->pVdbe = sqliteVdbeCreate(pParse->db->pBe);
}
if( v==0 ) goto select_cleanup;
if( v==0 ){
sqliteSetString(&pParse->zErrMsg, "out of memory", 0);
pParse->nErr++;
return 1;
}
if( pOrderBy ){
sqliteVdbeAddOp(v, OP_SortOpen, 0, 0, 0, 0);
}
@@ -201,7 +270,7 @@ void sqliteSelect(
sqliteVdbeAddOp(v, OP_Open, distinct, 1, 0, 0);
}
pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0);
if( pWInfo==0 ) goto select_cleanup;
if( pWInfo==0 ) return 1;
/* Pull the requested fields.
*/
@@ -232,7 +301,7 @@ void sqliteSelect(
char *zSortOrder;
sqliteVdbeAddOp(v, OP_SortMakeRec, pEList->nExpr, 0, 0, 0);
zSortOrder = sqliteMalloc( pOrderBy->nExpr + 1 );
if( zSortOrder==0 ) goto select_cleanup;
if( zSortOrder==0 ) return 1;
for(i=0; i<pOrderBy->nExpr; i++){
zSortOrder[i] = pOrderBy->a[i].idx ? '-' : '+';
sqliteExprCode(pParse, pOrderBy->a[i].pExpr);
@@ -288,14 +357,5 @@ void sqliteSelect(
if( isAgg ){
sqliteVdbeAddOp(v, OP_Callback, pEList->nExpr, 0, 0, 0);
}
/* Always execute the following code before exiting, in order to
** release resources.
*/
select_cleanup:
sqliteExprListDelete(pEList);
sqliteIdListDelete(pTabList);
sqliteExprDelete(pWhere);
sqliteExprListDelete(pOrderBy);
return;
return 0;
}