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, 26 insertions, 1 deletions

diff --git a/mysql-test/r/metadata.result b/mysql-test/r/metadata.result
index 54b3f1e0466..d691a200b7e 100644
--- a/mysql-test/r/metadata.result
+++ b/mysql-test/r/metadata.result
@@ -55,8 +55,33 @@ id	data	data
 2	female	no
 select t1.id from t1 union select t2.id from t2;
 Catalog	Database	Table	Table_alias	Column	Column_alias	Name	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
-def	test	t1	t1	id	id	1	3	1	Y	32768	0	63
+def				id	id	1	4	1	Y	32768	0	63
 id
 1
 2
 drop table t1,t2;
+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;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Name	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def				@arg00	@arg00	8	20	1	Y	32768	0	63
+@arg00
+1
+select * from (select @arg00) aaa;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Name	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def			aaa	@arg00	@arg00	8	20	1	Y	32768	0	63
+@arg00
+1
+select 1 union select 1;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Name	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def				1	1	8	20	1	N	32769	0	63
+1
+1
+select * from (select 1 union select 1) aaa;
+Catalog	Database	Table	Table_alias	Column	Column_alias	Name	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
+def			aaa	1	1	8	20	1	N	32769	0	63
+1
+1
+drop table t1;