Fixed LP bug #874035.

The function Item_direct_view_ref::fix_fields erroneously did not correct
the value of the flag maybe_null when the view for which the item was
being fixed happened to be an inner table of an outer join.
 

mysql-test/r/derived_view.result

@@ -1764,4 +1764,27 @@ x
 set optimizer_switch= @save_optimizer_switch;
 DROP VIEW v3;
 DROP TABLE t1,t2,t3;
+#
+# Bug #874035: view as an inner table of a materialized derived
+#
+CREATE TABLE t2 (a int NOT NULL);
+INSERT INTO t2 VALUES (7), (4);
+CREATE TABLE t1 (b int NOT NULL);
+INSERT INTO t1 VALUES (5), (7);
+CREATE ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+SET SESSION optimizer_switch='derived_merge=off';
+PREPARE st1 FROM
+'SELECT * FROM (SELECT * FROM t2 LEFT JOIN v1 ON t2.a = v1.b) AS t';
+EXECUTE st1;
+a	b
+7	7
+4	NULL
+EXECUTE st1;
+a	b
+7	7
+4	NULL
+DEALLOCATE PREPARE st1;
+DROP VIEW v1;
+DROP TABLE t1,t2;
+SET SESSION optimizer_switch='derived_merge=on';
 set optimizer_switch=@exit_optimizer_switch;

mysql-test/t/derived_view.test

@@ -1166,5 +1166,29 @@ set optimizer_switch= @save_optimizer_switch;
 DROP VIEW v3;
 DROP TABLE t1,t2,t3;
 
+--echo #
+--echo # Bug #874035: view as an inner table of a materialized derived
+--echo #
+
+CREATE TABLE t2 (a int NOT NULL);
+INSERT INTO t2 VALUES (7), (4);
+
+CREATE TABLE t1 (b int NOT NULL);
+INSERT INTO t1 VALUES (5), (7);
+CREATE ALGORITHM=MERGE VIEW v1 AS SELECT * FROM t1;
+
+SET SESSION optimizer_switch='derived_merge=off';
+
+PREPARE st1 FROM
+'SELECT * FROM (SELECT * FROM t2 LEFT JOIN v1 ON t2.a = v1.b) AS t';
+EXECUTE st1;
+EXECUTE st1;
+DEALLOCATE PREPARE st1;
+
+DROP VIEW v1;
+DROP TABLE t1,t2;
+
+SET SESSION optimizer_switch='derived_merge=on';
+
 # The following command must be the last one the file 
 set optimizer_switch=@exit_optimizer_switch;

sql/item.cc

@@ -7321,7 +7321,11 @@ bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
            ((*ref)->fix_fields(thd, ref)))
     return TRUE;
 
-  return Item_direct_ref::fix_fields(thd, reference);
+  if (Item_direct_ref::fix_fields(thd, reference))
+    return TRUE;
+  if (view->table && view->table->maybe_null)
+    maybe_null= TRUE;
+  return FALSE;
 }
 
 /*