求教一个sql语句里传参怎么写

Question

UPDATE post SET content=(SELECT group_concat(id)ids FROM article WHERE pid = 'id') WHERE id < 720

如上，引号里的id要与where后的id相等

Answer 1

UPDATE post a SET content=(SELECT group_concat(id)ids FROM article WHERE pid = a.id) WHERE a.id < 720

就是个子查询