fixed union types merging and table related metadata (BUG#8824)

mysql-test/r/func_group.result:
  new result
mysql-test/r/metadata.result:
  new result
  test of metadata of variables, unions and derived tables
mysql-test/r/union.result:
  new results
  test of union of enum
mysql-test/t/metadata.test:
  test of metadata of variables, unions and derived tables
mysql-test/t/union.test:
  test of union of enum
sql/field.cc:
  Field type merging rules added
  Fixed table name/alias returting for field made from temporary tables
sql/field.h:
  removed unned field type reporting
sql/item.cc:
  fixed bug in NEW_DATE type field creartion
  replaced mechanism of merging types of UNION
sql/item.h:
  replaced mechanism of merging types of UNION
sql/item_func.h:
  new item type to make correct field type detection possible
sql/item_subselect.cc:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_derived.cc:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_lex.h:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_parse.cc:
  made function for enum/set pack length calculation
sql/sql_prepare.cc:
  added table name parameter to prepare() to show right table alias for derived tables
sql/sql_select.cc:
  new temporary table field creation by Item_type_holder
  fixed table alias for temporary table
sql/sql_union.cc:
  added table name parameter to prepare() to show right table alias for derived tables

1 files changed, 13 insertions, 0 deletions

diff --git a/mysql-test/t/metadata.test b/mysql-test/t/metadata.test
index d11cb62b04e..ebd58ef4ebb 100644
--- a/mysql-test/t/metadata.test
+++ b/mysql-test/t/metadata.test
@@ -34,4 +34,17 @@ select t1.id, t1.data, t2.data from t1, t2 where t1.id = t2.id order by t1.id;
 select t1.id from t1 union select t2.id from t2;
 drop table t1,t2;
 
+#
+# variables union and derived tables metadata test
+#
+create table t1 ( a int, b varchar(30), primary key(a));
+insert into t1 values (1,'one');
+insert into t1 values (2,'two');
+set @arg00=1 ;
+select @arg00 FROM t1 where a=1 union distinct select 1 FROM t1 where a=1;
+select * from (select @arg00) aaa;
+select 1 union select 1;
+select * from (select 1 union select 1) aaa;
+drop table t1;
+
 --disable_metadata