Add new routines to simplify dealing with collating sequences in expressions:
sqlite3ExprNNCollSeq() and sqlite3ExprCollSeqMatch().
FossilOrigin-Name: 490e488ea963fe725b16212822c8608f2b6abce688931b611446bc2cbfe6b87c
diff --git a/src/expr.c b/src/expr.c
index b482faf..8282c99 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -124,6 +124,11 @@
** Return the collation sequence for the expression pExpr. If
** there is no defined collating sequence, return NULL.
**
+** See also: sqlite3ExprNNCollSeq()
+**
+** The sqlite3ExprNNCollSeq() works the same exact that it returns the
+** default collation if pExpr has no defined collation.
+**
** The collating sequence might be determined by a COLLATE operator
** or by the presence of a column with a defined collating sequence.
** COLLATE operators take first precedence. Left operands take
@@ -189,6 +194,32 @@
}
/*
+** Return the collation sequence for the expression pExpr. If
+** there is no defined collating sequence, return a pointer to the
+** defautl collation sequence.
+**
+** See also: sqlite3ExprCollSeq()
+**
+** The sqlite3ExprCollSeq() routine works the same except that it
+** returns NULL if there is no defined collation.
+*/
+CollSeq *sqlite3ExprNNCollSeq(Parse *pParse, Expr *pExpr){
+ CollSeq *p = sqlite3ExprCollSeq(pParse, pExpr);
+ if( p==0 ) p = pParse->db->pDfltColl;
+ assert( p!=0 );
+ return p;
+}
+
+/*
+** Return TRUE if the two expressions have equivalent collating sequences.
+*/
+int sqlite3ExprCollSeqMatch(Parse *pParse, Expr *pE1, Expr *pE2){
+ CollSeq *pColl1 = sqlite3ExprNNCollSeq(pParse, pE1);
+ CollSeq *pColl2 = sqlite3ExprNNCollSeq(pParse, pE2);
+ return sqlite3StrICmp(pColl1->zName, pColl2->zName)==0;
+}
+
+/*
** pExpr is an operand of a comparison operator. aff2 is the
** type affinity of the other operand. This routine returns the
** type affinity that should be used for the comparison operator.
@@ -1843,8 +1874,8 @@
for(i=0; i<pGroupBy->nExpr; i++){
Expr *p = pGroupBy->a[i].pExpr;
if( sqlite3ExprCompare(0, pExpr, p, -1)<2 ){
- CollSeq *pColl = sqlite3ExprCollSeq(pWalker->pParse, p);
- if( pColl==0 || sqlite3_stricmp("BINARY", pColl->zName)==0 ){
+ CollSeq *pColl = sqlite3ExprNNCollSeq(pWalker->pParse, p);
+ if( sqlite3_stricmp("BINARY", pColl->zName)==0 ){
return WRC_Prune;
}
}