diff options
Diffstat (limited to 'src/expr.c')
-rw-r--r-- | src/expr.c | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/src/expr.c b/src/expr.c index c8dfd3af3..3f040309a 100644 --- a/src/expr.c +++ b/src/expr.c @@ -2428,6 +2428,7 @@ static int exprComputeOperands( VdbeComment((v, "skip left operand")); VdbeCoverage(v); }else{ + r2 = 0; /* Silence a false-positive uninit-var warning in MSVC */ addrIsNull = 0; } r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, pFree1); @@ -3896,17 +3897,23 @@ int sqlite3CodeSubselect(Parse *pParse, Expr *pExpr){ VdbeComment((v, "Init EXISTS result")); } if( pSel->pLimit ){ - /* The subquery already has a limit. If the pre-existing limit is X - ** then make the new limit X<>0 so that the new limit is either 1 or 0 */ - sqlite3 *db = pParse->db; - pLimit = sqlite3Expr(db, TK_INTEGER, "0"); - if( pLimit ){ - pLimit->affExpr = SQLITE_AFF_NUMERIC; - pLimit = sqlite3PExpr(pParse, TK_NE, - sqlite3ExprDup(db, pSel->pLimit->pLeft, 0), pLimit); - } - sqlite3ExprDeferredDelete(pParse, pSel->pLimit->pLeft); - pSel->pLimit->pLeft = pLimit; + /* The subquery already has a limit. If the pre-existing limit X is + ** not already integer value 1 or 0, then make the new limit X<>0 so that + ** the new limit is either 1 or 0 */ + Expr *pLeft = pSel->pLimit->pLeft; + if( ExprHasProperty(pLeft, EP_IntValue)==0 + || (pLeft->u.iValue!=1 && pLeft->u.iValue!=0) + ){ + sqlite3 *db = pParse->db; + pLimit = sqlite3Expr(db, TK_INTEGER, "0"); + if( pLimit ){ + pLimit->affExpr = SQLITE_AFF_NUMERIC; + pLimit = sqlite3PExpr(pParse, TK_NE, + sqlite3ExprDup(db, pLeft, 0), pLimit); + } + sqlite3ExprDeferredDelete(pParse, pLeft); + pSel->pLimit->pLeft = pLimit; + } }else{ /* If there is no pre-existing limit add a limit of 1 */ pLimit = sqlite3Expr(pParse->db, TK_INTEGER, "1"); |