Fixed LP bug #806097.

The value of THD::used tables should be re-evaluated after merges
of views and derived tables into the main query. 
Now it's done in the function SELECT_LEX::update_used_tables.
The re-evaluation of the 'used_table' bitmaps for the items
in HAVING, GROUP BY and ORDER BY clauses has been added as well.
 

mysql-test/r/derived_view.result

@@ -900,3 +900,45 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
+#
+# LP bug #806097: left join over a view + DISTINCT           
+#
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (252,6), (232,0), (174,232);
+CREATE TABLE t2 (a int);
+INSERT INTO t2 VALUES (232), (174);
+CREATE TABLE t3 (c int);
+INSERT INTO t3 VALUES (1), (2);
+CREATE VIEW v1 AS SELECT t2.a FROM t3,t2;
+SELECT v1.a FROM t1 LEFT JOIN v1 ON t1.b = 0;
+a
+NULL
+232
+174
+232
+174
+NULL
+SELECT DISTINCT t2.a FROM t1 LEFT JOIN (t3,t2) ON t1.b = 0;
+a
+NULL
+232
+174
+EXPLAIN
+SELECT DISTINCT t2.a FROM t1 LEFT JOIN (t3,t2) ON t1.b = 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using temporary
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	
+SELECT DISTINCT v1.a FROM t1 LEFT JOIN v1 ON t1.b = 0;
+a
+NULL
+232
+174
+EXPLAIN
+SELECT DISTINCT v1.a FROM t1 LEFT JOIN v1 ON t1.b = 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using temporary
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	
+DROP VIEW v1;
+DROP TABLE t1,t2,t3;

mysql-test/r/func_gconcat.result

@@ -985,8 +985,8 @@ EXPLAIN EXTENDED SELECT 1 FROM
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	100.00	Using join buffer (flat, BNL join)
-2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort
-2	DERIVED	td	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary; Using filesort; Distinct
+2	DERIVED	td	ALL	NULL	NULL	NULL	NULL	2	100.00	Distinct; Using join buffer (flat, BNL join)
 Warnings:
 Note	1003	select 1 AS `1` from (select distinct group_concat(`test`.`td`.`f1` separator ',') AS `GROUP_CONCAT(td.f1)` from `test`.`t1` join `test`.`t1` `td` group by `test`.`td`.`f1`) `d` join `test`.`t1`
 SELECT 1 FROM

mysql-test/t/derived_view.test

@@ -503,3 +503,31 @@ SELECT * FROM v1 t
 
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
+
+--echo #
+--echo # LP bug #806097: left join over a view + DISTINCT           
+--echo #
+
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (252,6), (232,0), (174,232);
+
+CREATE TABLE t2 (a int);
+INSERT INTO t2 VALUES (232), (174);
+
+CREATE TABLE t3 (c int);
+INSERT INTO t3 VALUES (1), (2);
+
+CREATE VIEW v1 AS SELECT t2.a FROM t3,t2;
+
+SELECT v1.a FROM t1 LEFT JOIN v1 ON t1.b = 0;
+
+SELECT DISTINCT t2.a FROM t1 LEFT JOIN (t3,t2) ON t1.b = 0;
+EXPLAIN
+SELECT DISTINCT t2.a FROM t1 LEFT JOIN (t3,t2) ON t1.b = 0;
+
+SELECT DISTINCT v1.a FROM t1 LEFT JOIN v1 ON t1.b = 0;
+EXPLAIN
+SELECT DISTINCT v1.a FROM t1 LEFT JOIN v1 ON t1.b = 0;
+
+DROP VIEW v1;
+DROP TABLE t1,t2,t3;

sql/sql_lex.cc

@@ -3501,6 +3501,33 @@ void SELECT_LEX::update_used_tables()
     join->conds->update_used_tables();
     join->conds->walk(&Item::eval_not_null_tables, 0, NULL);
   }
+  if (join->having)
+  {
+    join->having->update_used_tables();
+  }
+
+  Item *item;
+  List_iterator_fast<Item> it(join->fields_list);
+  while ((item= it++))
+  {
+    item->update_used_tables();
+    join->thd->used_tables|= item->used_tables();
+  }
+  Item_outer_ref *ref;
+  List_iterator_fast<Item_outer_ref> ref_it(inner_refs_list);
+  while ((ref= ref_it++))
+  {
+    item= ref->outer_ref;
+    item->update_used_tables();
+    join->thd->used_tables|= item->used_tables();
+  }
+  for (ORDER *order= group_list.first; order; order= order->next)
+    (*order->item)->update_used_tables();
+  if (!master_unit()->is_union())
+  {
+    for (ORDER *order= order_list.first; order; order= order->next)
+      (*order->item)->update_used_tables();
+  }      
 }
 
 

sql/sql_select.cc

@@ -880,6 +880,8 @@ JOIN::optimize()
 
   if (select_lex->first_cond_optimization)
   {
+    if (!select_lex->outer_select())
+      thd->used_tables= 0; 
     //Do it only for the first execution
     /* Merge all mergeable derived tables/views in this SELECT. */
     if (select_lex->handle_derived(thd->lex, DT_MERGE))
@@ -893,6 +895,8 @@ JOIN::optimize()
 
   if (select_lex->first_cond_optimization)
   {
+    if (!select_lex->outer_select())
+      thd->used_tables= 0;
     /* dump_TABLE_LIST_graph(select_lex, select_lex->leaf_tables); */
     if (convert_join_subqueries_to_semijoins(this))
       DBUG_RETURN(1); /* purecov: inspected */