fixed deleting derived table tree after using (BUG#1536)

mysql-test/r/subselect.result:
  fixed drop table statement
  test for BUG#1536
mysql-test/t/subselect.test:
  fixed drop table statement
  test for BUG#1536
sql/sql_derived.cc:
  all tree of derived table should be deleted
sql/sql_lex.cc:
  delete subtree method
sql/sql_lex.h:
  delete subtree method

mysql-test/r/subselect.result

@@ -1438,4 +1438,11 @@ explain select * from t3 where a > all (select max(b) from t2 group by a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
-drop table if exists t2, t3;
+drop table t2, t3;
+create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
+);
+insert into t1 VALUES(1,1,1), (2,2,1);
+select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
+count(*)
+2
+drop table t1;

mysql-test/t/subselect.test

@@ -964,4 +964,13 @@ explain select * from t3 where a >= all (select b from t2);
 insert into t2 values (2,2), (2,1), (3,3), (3,1);
 select * from t3 where a > all (select max(b) from t2 group by a);
 explain select * from t3 where a > all (select max(b) from t2 group by a);
-drop table if exists t2, t3;
+drop table t2, t3;
+
+#
+# deived tables with subquery inside all by one table
+#
+create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
+);
+insert into t1 VALUES(1,1,1), (2,2,1);
+select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
+drop table t1;

sql/sql_derived.cc

@@ -220,7 +220,7 @@ int mysql_derived(THD *thd, LEX *lex, SELECT_LEX_UNIT *unit,
 	    }
 	  }
 	  else
-	    unit->exclude_level();
+	    unit->exclude_tree();
 	  org_table_list->db= (char *)"";
 #ifndef DBUG_OFF
 	  /* Try to catch errors if this is accessed */

sql/sql_lex.cc

@@ -1097,6 +1097,16 @@ void st_select_lex_node::exclude()
   */
 }
 
+
+/*
+  Exclude level of current unit from tree of SELECTs
+
+  SYNOPSYS
+    st_select_lex_unit::exclude_level()
+
+  NOTE: units which belong to current will be brought up on level of
+  currernt unit 
+*/
 void st_select_lex_unit::exclude_level()
 {
   SELECT_LEX_UNIT *units= 0, **units_last= &units;
@@ -1125,6 +1135,30 @@ void st_select_lex_unit::exclude_level()
     (*prev)= next;
 }
 
+
+/*
+  Exclude subtree of current unit from tree of SELECTs
+
+  SYNOPSYS
+    st_select_lex_unit::exclude_tree()
+*/
+void st_select_lex_unit::exclude_tree()
+{
+  SELECT_LEX_UNIT *units= 0, **units_last= &units;
+  for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
+  {
+    if (sl->link_prev && (*sl->link_prev= sl->link_next))
+      sl->link_next->link_prev= sl->link_prev;
+
+    for (SELECT_LEX_UNIT *u= sl->first_inner_unit(); u; u= u->next_unit())
+    {
+      u->exclude_level();
+    }
+  }
+  (*prev)= next;
+}
+
+
 /*
   st_select_lex_node::mark_as_dependent mark all st_select_lex struct from 
   this to 'last' as dependent
@@ -1135,7 +1169,6 @@ void st_select_lex_unit::exclude_level()
 
   NOTE
     'last' should be reachable from this st_select_lex_node
-
 */
 
 void st_select_lex::mark_as_dependent(SELECT_LEX *last)

sql/sql_lex.h

@@ -321,6 +321,7 @@ class st_select_lex_unit: public st_select_lex_node {
   st_select_lex_unit* next_unit() { return (st_select_lex_unit*) next; }
   st_select_lex* return_after_parsing() { return return_to; }
   void exclude_level();
+  void exclude_tree();
 
   /* UNION methods */
   int prepare(THD *thd, select_result *result, bool tables_and_fields_initied);