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