1 files changed, 12 insertions, 12 deletions
diff --git a/src/window.c b/src/window.c
index dcd7107a4..ed39107b9 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1196,17 +1196,14 @@ void sqlite3WindowChain(Parse *pParse, Window *pWin, Window *pList){
 void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){
   if( p ){
     assert( p->op==TK_FUNCTION );
-    /* This routine is only called for the parser.  If pWin was not
-    ** allocated due to an OOM, then the parser would fail before ever
-    ** invoking this routine */
-    if( ALWAYS(pWin) ){
-      p->y.pWin = pWin;
-      ExprSetProperty(p, EP_WinFunc);
-      pWin->pOwner = p;
-      if( p->flags & EP_Distinct ){
-        sqlite3ErrorMsg(pParse,
-           "DISTINCT is not supported for window functions");
-      }
+    assert( pWin );
+    p->y.pWin = pWin;
+    ExprSetProperty(p, EP_WinFunc);
+    pWin->pOwner = p;
+    if( (p->flags & EP_Distinct) && pWin->eFrmType!=TK_FILTER ){
+      sqlite3ErrorMsg(pParse,
+          "DISTINCT is not supported for window functions"
+      );
     }
   }else{
     sqlite3WindowDelete(pParse->db, pWin);
@@ -1217,7 +1214,7 @@ void sqlite3WindowAttach(Parse *pParse, Expr *p, Window *pWin){
 ** Return 0 if the two window objects are identical, or non-zero otherwise.
 ** Identical window objects can be processed in a single scan.
 */
-int sqlite3WindowCompare(Parse *pParse, Window *p1, Window *p2){
+int sqlite3WindowCompare(Parse *pParse, Window *p1, Window *p2, int bFilter){
   if( p1->eFrmType!=p2->eFrmType ) return 1;
   if( p1->eStart!=p2->eStart ) return 1;
   if( p1->eEnd!=p2->eEnd ) return 1;
@@ -1226,6 +1223,9 @@ int sqlite3WindowCompare(Parse *pParse, Window *p1, Window *p2){
   if( sqlite3ExprCompare(pParse, p1->pEnd, p2->pEnd, -1) ) return 1;
   if( sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1) ) return 1;
   if( sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1) ) return 1;
+  if( bFilter ){
+    if( sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1) ) return 1;
+  }
   return 0;
 }