join_nested.result, join_nested.test:

  Added a teast case for bug #11284.
sql_select.cc:
  Fixed bug #11284.
  Optimization with empty inner table currently cannot be
  used in the case of nested outer join.


sql/sql_select.cc:
  Fixed bug #11284.
  Optimization with empty inner table currently cannot be
  used in the case of nested outer join.
mysql-test/t/join_nested.test:
  Added a teast case for bug #11284.

mysql-test/r/join_nested.result

@@ -1321,3 +1321,25 @@ NULL	NULL	NULL
 18	NULL	NULL
 19	NULL	NULL
 DROP TABLE t1,t2,t3;
+CREATE TABLE t1 (c11 int);
+CREATE TABLE t2 (c21 int);
+CREATE TABLE t3 (c31 int);
+INSERT INTO t1 VALUES (4), (5);
+SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
+c11	c21
+4	NULL
+5	NULL
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	0	const row not found
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
+c11	c21	c31
+4	NULL	NULL
+5	NULL	NULL
+EXPLAIN SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	
+DROP TABLE t1,t2,t3;

mysql-test/t/join_nested.test

@@ -752,3 +752,21 @@ EXPLAIN SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
 SELECT a, b, c FROM t1 LEFT JOIN (t2, t3) ON b < 3 and b = c;
 
 DROP TABLE t1,t2,t3;
+
+#
+# Test for bug #11284: empty table in a nested left join
+# 
+
+CREATE TABLE t1 (c11 int);
+CREATE TABLE t2 (c21 int);
+CREATE TABLE t3 (c31 int);
+
+INSERT INTO t1 VALUES (4), (5);
+
+SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON c11=c21;
+
+SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
+EXPLAIN SELECT * FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON c21=c31) ON c11=c21;
+
+DROP TABLE t1,t2,t3;

sql/sql_select.cc

@@ -2158,7 +2158,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds,
     if (*s->on_expr_ref)
     {
       /* s is the only inner table of an outer join */
-      if (!table->file->records)
+      if (!table->file->records && !embedding)
       {						// Empty table
         s->dependent= 0;                        // Ignore LEFT JOIN depend.
 	set_position(join,const_count++,s,(KEYUSE*) 0);