update的格式是
update t1 set t1.name=’Liu’ from t1 inner join t2 on t1.id = t2.tid
delete 语句也是类似
delete from t1 from t1 inner join t2 on t1.id = t2.tid
SQL中使用update inner join和delete inner join
原文：http://www.cnblogs.com/blueoverflow/p/4797008.html
