SQL Update多表联合更新的方法 distinct[去除重复字段]

// SQL Update多表联合更新的方法 distinct[去除重复字段]

update table as t set has_attachments = 1 ,topicid=(select distinct topicid from zoon_attachments as t2 where topicid = t.topicid );

update A,B,C set A.ls=C.ls where A.bmid=B.bmid and B.dj=C.dj;

或者：

update A as a,B as b,C as c set a.ls=c.ls where a.bmid=b.bmid and b.dj=c.dj;

//根据表查询 修改其他表中满足条件的其他字段的值

update zoon_topics as t , zoon_attachments as a set has_attachments = 1 where t.topicid=a.t