Какой нужен запрос в БД для изменения значения дополнительного поля новости?

UPDATE dle_post SET xfields = 
(

SELECT new_string FROM ( SELECT

@xfield_find_str := 'test_date', # xfields name

@xfield_new_str := `date`, # replace xfields to

@parse_query := SUBSTRING_INDEX( SUBSTRING_INDEX( xfields , CONCAT( @xfield_find_str, '|' ), -1 ), '||', 1 ),

IF (
@parse_query = '', 
xfields, 
REPLACE( xfields, CONCAT( CONCAT( @xfield_find_str, '|' ), @parse_query ), CONCAT( @xfield_find_str, '|', @xfield_new_str ) )
) new_string

FROM dle_post WHERE id = 5 ) new_xfields

) WHERE id = 5

UPDATE dle_post SET xfields = 
(

SELECT new_string FROM ( SELECT

@xfield_find_str := 'test_date', # xfields name

@xfield_new_str := `date`, # replace xfields to

@parse_query := SUBSTRING_INDEX( SUBSTRING_INDEX( xfields , CONCAT( @xfield_find_str, '|' ), -1 ), '||', 1 ),

REPLACE( xfields, CONCAT( CONCAT( @xfield_find_str, '|' ), @parse_query ), CONCAT( @xfield_find_str, '|', @xfield_new_str ) ) new_string

FROM dle_post WHERE id = 5 ) new_xfields

) WHERE id = 5

test_date|2015-02-02 00:35:09||test_date_2|2015-06-05 00:00:09

test_date|2015-09-05 00:38:11||test_date_2|2015-06-05 00:00:09