mysql关联删除

1、从数据表t1中把那些id值在数据表t2里有匹配的记录全删除掉1  

 DELETE t1 FROM t1,t2 WHERE t1.id=t2.id 
 DELETE FROM t1 USING t1,t2 WHERE t1.id=t2.id

2、从数据表t1里在数据表t2里没有匹配的记录查找出来并删除掉1  

DELETE t1 FROM t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL 
DELETE FROM t1,USING t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL

3.从两个表中找出相同记录的数据并把两个表中的数据都删除掉1

DELETE t1,t2 from t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t1.id=25

注意此处的delete t1,t2 from 中的t1,t2不能是别名

delete t1,t2 from table_name as t1 left join table2_name as t2 on t1.id=t2.id where table_name.id=25（MYSQL 版本不小于5.0在5.0中是可以的）

delete table_name,table2_name from table_name as t1 left join table2_name as t2 on t1.id=t2.id where table_name.id=25