Assert that if two functions compare equal in every other way, then they

must both have OVER clauses, or neither has an OVER clause.  Use this fact
to simplify expression comparison.

FossilOrigin-Name: 52559ad58ce412af40f1f34e80bfe9fadc6a93f3ca0cfaf69f94d615bbb99831

1 files changed, 10 insertions, 3 deletions

diff --git a/src/expr.c b/src/expr.c
index 10a1dc67f..a329ef413 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -4952,11 +4952,18 @@ int sqlite3ExprCompare(Parse *pParse, Expr *pA, Expr *pB, int iTab){
        && (pA->iTable!=iTab || NEVER(pB->iTable>=0)) ) return 2;
     }
 #ifndef SQLITE_OMIT_WINDOWFUNC
+    /* Justification for the assert():
+    /* window functions have p->op==TK_FUNCTION but aggregate functions
+    ** have p->op==TK_AGG_FUNCTION.  So any comparison between an aggregate
+    ** function and a window function should have failed before reaching
+    ** this point.  And, it is not possible to have a window function and
+    ** a scalar function with the same name and number of arguments.  So
+    ** if we reach this point, either A and B both window functions or
+    ** neither are a window functions. */
+    assert( (pA->pWin==0)==(pB->pWin==0) );
+
     if( pA->pWin!=0 ){
-      if( pB->pWin==0 ) return 2;
       if( sqlite3WindowCompare(pParse,pA->pWin,pB->pWin)!=0 ) return 2;
-    }else if( pB->pWin!=0 ){
-      return 2;
     }
 #endif
   }