学习 mysql 语句

select id,CONCAT(CAST(id AS CHAR),' ',REPLACE(ifnull(brand,''),',',' '),' ',REPLACE(ifnull(model,''),"NULL",' '),' ',name) as name,CONCAT(CAST(category_id AS CHAR),',',CAST(category_l2 AS CHR),',',CAST(category_l1 AS CHAR)) as category_id,available,price,user_code,sales_volume,hits,price_spread,match_status,create_time,update_time from product where enabled=1 and update_time>