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added DISTINCT on select (CVS 27)

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FossilOrigin-Name: 1f0c4ffd98591e506201b6b0e6e60b9216ceb596
This commit is contained in:
drh
2000-05-31 20:00:52 +00:00
parent ec86adb88b
commit efb7251d6e
11 changed files with 316 additions and 178 deletions
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30
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 1.2 2000/05/31 18:20:14 drh Exp $
** $Id: select.c,v 1.3 2000/05/31 20:00:52 drh Exp $
*/
#include "sqliteInt.h"
@@ -37,7 +37,8 @@ void sqliteSelect(
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 */
ExprList *pOrderBy, /* The ORDER BY clause. May be NULL */
int distinct /* If true, only output distinct results */
){
int i, j;
WhereInfo *pWInfo;
@@ -121,6 +122,12 @@ void sqliteSelect(
pOrderBy = 0;
}
/* Turn off distinct if this is an aggregate
*/
if( isAgg ){
distinct = 0;
}
/* Begin generating code.
*/
v = pParse->pVdbe;
@@ -188,7 +195,11 @@ void sqliteSelect(
}
/* Begin the database scan
*/
*/
if( distinct ){
distinct = pTabList->nId*2+1;
sqliteVdbeAddOp(v, OP_Open, distinct, 0, 0, 0);
}
pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 0);
if( pWInfo==0 ) goto select_cleanup;
@@ -199,6 +210,19 @@ void sqliteSelect(
sqliteExprCode(pParse, pEList->a[i].pExpr);
}
}
/* If the current result is not distinct, script the remainder
** of this processing.
*/
if( distinct ){
int isDistinct = sqliteVdbeMakeLabel(v);
sqliteVdbeAddOp(v, OP_MakeKey, pEList->nExpr, 1, 0, 0);
sqliteVdbeAddOp(v, OP_Distinct, distinct, isDistinct, 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_Put, distinct, 0, 0, 0);
}
/* If there is no ORDER BY clause, then we can invoke the callback
** right away. If there is an ORDER BY, then we need to put the