MySQL多表关联数据同时删除sql语句

MySQL多表关联数据同时删除sql语句 有需要的朋友可参考。

DELETE删除多表数据，怎样才能同时删除多个关联表的数据呢？这里做了深入的解释：

代码如下	复制代码
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 where 条件

category（栏目信息表）和news（新闻数据表）。

category中的id（栏目编号）字段作为该表的主键（primary key）.唯一标识了一个栏目的信息。
news 中的id字段作为该表的主键（primary key）.唯一标识了一个栏目的信息。

category_id（栏目编号）字段与category表的id字段相关联。

1.SQL删除语句

 代码如下

复制代码

代码如下	复制代码
delete category,news from category left join news on category.id = news.category_id

delete category,news from category left join news on category.id = news.category_id

代码如下	复制代码
DELETE t1 FROM t1,t2 WHERE t1.id=t2.id 或 DELETE FROM t1 USING t1,t2 WHERE t1.id=t2.id

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  

代码如下	复制代码
DELETE t1 FROM t1,t2 WHERE t1.id=t2.id 或 DELETE FROM t1 USING t1,t2 WHERE t1.id=t2.id

代码如下	复制代码
DELETE t1 FROM t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL 或 DELETE FROM t1,USING t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL

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  

代码如下	复制代码
DELETE t1 FROM t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL 或 DELETE FROM t1,USING t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL

代码如下	复制代码
DELETE t1,t2 from t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t1.id=25

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  
 

代码如下	复制代码
delete t1,t2 from table_name as t1 left join table2_name as t2 on t1.id=t2.id where table_name.id=25

注意此处的delete t1,t2 from 中的t1,t2不能是别名 如：1  

代码如下	复制代码
delete t1,t2 from table_name as t1 left join table2_name as t2 on t1.id=t2.id where table_name.id=25

在数据里面执行是错误的（MYSQL 版本不小于5.0在5.0中是可以的）

上述语句改 写成1  
 

 代码如下

复制代码

 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

代码如下	复制代码
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