commit f9463dfbcf8069bb1df1dd3407bc6e2837f9cee6
author drh <drh@noemail.net> Sat Feb 11 14:59:58 2017 +0000
committer drh <drh@noemail.net> Sat Feb 11 14:59:58 2017 +0000
tree db4610c4625f5d1909ddd056a34d04adfb085522
parent 13ac46eea2effd6e6f6033e062b760665bf4b7d3

Fix indexes on expressions so that they can be actually used with
a COLLATE clause.

FossilOrigin-Name: e464b919f76520b45bb58983c6702db59d820ee4

src/expr.c

diff --git a/src/expr.c b/src/expr.c
index ff4f1b5..6a1a928 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4681,6 +4681,17 @@
 }
 
 /*
+** Like sqlite3ExprCompare() except COLLATE operators at the top-level
+** are ignored.
+*/
+int sqlite3ExprCompareSkip(Expr *pA, Expr *pB, int iTab){
+  return sqlite3ExprCompare(
+             sqlite3ExprSkipCollate(pA),
+             sqlite3ExprSkipCollate(pB),
+             iTab);
+}
+
+/*
 ** Return true if we can prove the pE2 will always be true if pE1 is
 ** true.  Return false if we cannot complete the proof or if pE2 might
 ** be false.  Examples:

src/sqliteInt.h

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index f976889..23b4dd94 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3762,6 +3762,7 @@
 int sqlite3RunVacuum(char**, sqlite3*, int);
 char *sqlite3NameFromToken(sqlite3*, Token*);
 int sqlite3ExprCompare(Expr*, Expr*, int);
+int sqlite3ExprCompareSkip(Expr*, Expr*, int);
 int sqlite3ExprListCompare(ExprList*, ExprList*, int);
 int sqlite3ExprImpliesExpr(Expr*, Expr*, int);
 void sqlite3ExprAnalyzeAggregates(NameContext*, Expr*);

src/where.c

diff --git a/src/where.c b/src/where.c
index 80dfa20..4c533aa 100644
--- a/src/where.c
+++ b/src/where.c
@@ -209,7 +209,8 @@
         if( pTerm->leftCursor==iCur
          && pTerm->u.leftColumn==iColumn
          && (iColumn!=XN_EXPR
-             || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0)
+             || sqlite3ExprCompareSkip(pTerm->pExpr->pLeft,
+                                       pScan->pIdxExpr,iCur)==0)
          && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin))
         ){
           if( (pTerm->eOperator & WO_EQUIV)!=0

src/whereexpr.c

diff --git a/src/whereexpr.c b/src/whereexpr.c
index f511452..248b534 100644
--- a/src/whereexpr.c
+++ b/src/whereexpr.c
@@ -874,7 +874,7 @@
     if( pIdx->aColExpr==0 ) continue;
     for(i=0; i<pIdx->nKeyCol; i++){
       if( pIdx->aiColumn[i]!=XN_EXPR ) continue;
-      if( sqlite3ExprCompare(pExpr, pIdx->aColExpr->a[i].pExpr, iCur)==0 ){
+      if( sqlite3ExprCompareSkip(pExpr, pIdx->aColExpr->a[i].pExpr, iCur)==0 ){
         *piCur = iCur;
         *piColumn = XN_EXPR;
         return 1;