摘要：
一、DELETE删除多表数据，怎么才能同时删除多个关联表的数据呢 1. delete from t1 where 条件 2. delete t1 from t1 where 条件 3. delete t1 from t1,t2 where 条件 4. delete t1,t2 from t1,t2 阅读全文
摘要：
一、当用一个表中的数据来更新另外一个表中的数据时（两张表要有关联）： 1. update t1 set t1.c2 = t2.c2 from t2 where t1.c1 = t2.c1 2. update t1 set t1.c2 = t2.c2 from t1 inner join t2 on 阅读全文