join_outer.test, join_outer.result:

  Added test cases for bug #9938.
item.h:
  Fixed bug #9938: missing method not_null_tables for Item_ref.

mysql-test/r/join_outer.result

@@ -957,3 +957,21 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	const	PRIMARY,id	PRIMARY	14	const,const,const,const	1	Using index
 1	SIMPLE	t3	const	PRIMARY	PRIMARY	3	const,const	1	
 drop tables t1,t2,t3;
+CREATE TABLE t1 (EMPNUM INT, GRP INT);
+INSERT INTO t1 VALUES (0, 10);
+INSERT INTO t1 VALUES (2, 30);
+CREATE TABLE t2 (EMPNUM INT, NAME CHAR(5));
+INSERT INTO t2 VALUES (0, 'KERI');
+INSERT INTO t2 VALUES (9, 'BARRY');
+CREATE VIEW v1 AS
+SELECT COALESCE(t2.EMPNUM,t1.EMPNUM) AS EMPNUM, NAME, GRP
+FROM t2 LEFT OUTER JOIN t1 ON t2.EMPNUM=t1.EMPNUM;
+SELECT * FROM v1;
+EMPNUM	NAME	GRP
+0	KERI	10
+9	BARRY	NULL
+SELECT * FROM v1 WHERE EMPNUM < 10;
+EMPNUM	NAME	GRP
+0	KERI	10
+9	BARRY	NULL
+DROP TABLE t1,t2;

mysql-test/t/join_outer.test

@@ -676,3 +676,26 @@ left join t3 on t1.art = t3.id where t2.id =1 and t2.x = -5 and t2.y =-8
 and t1.gid =1 and t2.gid =1 and t3.set_id =1;
 drop tables t1,t2,t3;
 
+#
+# Test for bug #9938: invalid conversion from outer join to inner join 
+# for queries containing indirect reference in WHERE clause
+#
+
+CREATE TABLE t1 (EMPNUM INT, GRP INT);
+INSERT INTO t1 VALUES (0, 10);
+INSERT INTO t1 VALUES (2, 30);
+
+CREATE TABLE t2 (EMPNUM INT, NAME CHAR(5));
+INSERT INTO t2 VALUES (0, 'KERI');
+INSERT INTO t2 VALUES (9, 'BARRY');
+
+CREATE VIEW v1 AS
+SELECT COALESCE(t2.EMPNUM,t1.EMPNUM) AS EMPNUM, NAME, GRP
+  FROM t2 LEFT OUTER JOIN t1 ON t2.EMPNUM=t1.EMPNUM;
+
+SELECT * FROM v1;
+SELECT * FROM v1 WHERE EMPNUM < 10;
+
+DROP TABLE t1,t2;
+
+

sql/item.h

@@ -1325,6 +1325,7 @@ class Item_ref :public Item_ident
   { 
     return depended_from ? OUTER_REF_TABLE_BIT : (*ref)->used_tables(); 
   }
+  table_map not_null_tables() const { return (*ref)->not_null_tables(); }
   void set_result_field(Field *field)	{ result_field= field; }
   bool is_result_field() { return 1; }
   void save_in_result_field(bool no_conversions)