sql_select.cc:

  Fixed bug #11479.
  The JOIN::reinit method cannot call setup_tables
  after the optimization phase since this function
  removes some optimization settings for joined
  tables. E.g. it resets values of the null_row flag to 0.
subselect.result, subselect.test:
  Added a test case for bug #11479.

mysql-test/r/subselect.result

@@ -2817,3 +2817,19 @@ SELECT * FROM t1 WHERE (a,b) IN (('aaa','aaa'), ('aaa','bbb'));
 a	b
 aaa	aaa
 DROP TABLE t1;
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (a int, b int);
+CREATE TABLE t3 (b int NOT NULL);
+INSERT INTO t1 VALUES (1), (2), (3), (4);
+INSERT INTO t2 VALUES (1,10), (3,30);
+SELECT * FROM t2 LEFT JOIN t3 ON t2.b=t3.b
+WHERE t3.b IS NOT NULL OR t2.a > 10;
+a	b	b
+SELECT * FROM t1
+WHERE t1.a NOT IN (SELECT a FROM t2 LEFT JOIN t3 ON t2.b=t3.b
+WHERE t3.b IS NOT NULL OR t2.a > 10);
+a
+1
+2
+3
+4

mysql-test/t/subselect.test

@@ -1796,4 +1796,20 @@ SELECT * FROM t1 WHERE (a,b) IN (('aaa','aaa'), ('aaa','bbb'));
 
 DROP TABLE t1;
 
+#
+# Bug #11479: subquery over left join with an empty inner table 
+#
+
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (a int, b int);
+CREATE TABLE t3 (b int NOT NULL);
+INSERT INTO t1 VALUES (1), (2), (3), (4);
+INSERT INTO t2 VALUES (1,10), (3,30);
+
+SELECT * FROM t2 LEFT JOIN t3 ON t2.b=t3.b
+  WHERE t3.b IS NOT NULL OR t2.a > 10;
+SELECT * FROM t1
+  WHERE t1.a NOT IN (SELECT a FROM t2 LEFT JOIN t3 ON t2.b=t3.b
+                       WHERE t3.b IS NOT NULL OR t2.a > 10);
+
 # End of 4.1 tests

sql/sql_select.cc

@@ -984,7 +984,7 @@ JOIN::reinit()
   if (unit->select_limit_cnt == HA_POS_ERROR)
     select_lex->options&= ~OPTION_FOUND_ROWS;
   
-  if (setup_tables(tables_list))
+  if (!optimized && setup_tables(tables_list))
     DBUG_RETURN(1);
   
   /* Reset of sum functions */