Index: src/select.c
==================================================================
--- src/select.c
+++ src/select.c
@@ -4116,11 +4116,11 @@
 **           to suppress it. **)
 **
 **   (2) The inner query is the recursive part of a common table expression.
 **
 **   (3) The inner query has a LIMIT clause (since the changes to the WHERE
-**       close would change the meaning of the LIMIT).
+**       clause would change the meaning of the LIMIT).
 **
 **   (4) The inner query is the right operand of a LEFT JOIN and the
 **       expression to be pushed down does not come from the ON clause
 **       on that LEFT JOIN.
 **
@@ -4134,10 +4134,14 @@
 **           LEFT JOIN (SELECT 8 AS c3 UNION ALL SELECT 9) AS cc ON (b2=2);
 **
 **       The correct answer is three rows:  (1,1,NULL),(2,2,8),(2,2,9).
 **       But if the (b2=2) term were to be pushed down into the bb subquery,
 **       then the (1,1,NULL) row would be suppressed.
+**
+**   (6) The inner query features one or more window-functions (since 
+**       changes to the WHERE clause of the inner query could change the 
+**       window over which window functions are calculated).
 **
 ** Return 0 if no changes are made and non-zero if one or more WHERE clause
 ** terms are duplicated into the subquery.
 */
 static int pushDownWhereTerms(
@@ -4149,10 +4153,14 @@
 ){
   Expr *pNew;
   int nChng = 0;
   if( pWhere==0 ) return 0;
   if( pSubq->selFlags & SF_Recursive ) return 0;  /* restriction (2) */
+
+#ifndef SQLITE_OMIT_WINDOWFUNC
+  if( pSubq->pWin ) return 0;
+#endif
 
 #ifdef SQLITE_DEBUG
   /* Only the first term of a compound can have a WITH clause.  But make
   ** sure no other terms are marked SF_Recursive in case something changes
   ** in the future.

Index: test/window1.test
==================================================================
--- test/window1.test
+++ test/window1.test
@@ -368,8 +368,40 @@
     SELECT x, y, max(y) OVER xyz FROM t4
     WINDOW xyz AS (ORDER BY x)
   )
   SELECT *, min(z) OVER (ORDER BY x) FROM aaa ORDER BY 1;
 } {1 g g g   2 i i g   3 l l g   4 g l g   5 a l g   6 m m g}
+
+#-------------------------------------------------------------------------
+#
+do_execsql_test 10.0 {
+  CREATE TABLE sales(emp TEXT PRIMARY KEY, region, total);
+  INSERT INTO sales VALUES
+      ('Alice',     'North', 34),
+      ('Frank',     'South', 22),
+      ('Charles',   'North', 45),
+      ('Darrell',   'South', 8),
+      ('Grant',     'South', 23),
+      ('Brad' ,     'North', 22),
+      ('Elizabeth', 'South', 99),
+      ('Horace',    'East',   1);
+}
+
+# Best two salespeople from each region
+#
+do_execsql_test 10.1 {
+  SELECT emp, region, total FROM (
+    SELECT 
+      emp, region, total,
+      row_number() OVER (PARTITION BY region ORDER BY total DESC) AS rank
+    FROM sales
+  ) WHERE rank<=2 ORDER BY region, total DESC
+} {
+  Horace      East     1
+  Charles     North   45
+  Alice       North   34
+  Elizabeth   South   99
+  Grant       South   23
+}
 
 finish_test