SELECT GROUP_CONCAT(lv SEPARATOR ',') #lv FROM ( SELECT @pv :=( SELECT GROUP_CONCAT(cid SEPARATOR ',') FROM categories WHERE FIND_IN_SET(parent, @pv) ) AS lv FROM categories JOIN ( SELECT @pv := 5 ) tmp ) tmp2
SELECT GROUP_CONCAT(lv SEPARATOR ',') #lv FROM ( SELECT @pv :=( SELECT GROUP_CONCAT(cid SEPARATOR ',') FROM categories WHERE FIND_IN_SET(parent, @pv) ) AS lv FROM categories JOIN ( SELECT @pv := 5 ) tmp ) tmp2