mysql把一个表的字段update成另一个表的字段根据id

1.填充activity表里面的creator字段，用org的founderid,其中activity的orgid要和org的id对应，具体sql语句如下:
update activity a inner join (select id,founderid from org o) c on a.orgid =c.id set a.creator = c.founderid;