删除时，从表中基于2场条件

Question

在MySQL服务器中删除，我有3个表被叫用户的事情，thingfile

 
user 
uid, username, name, location, version 

thing 
thingid, username,, version 

thingfile 
thingid, code, version 

每个用户都有很多事情，每一件事情都有许多thingfiles 。

我会从用户表中删除象下面这样：

delete FROM user a WHERE a.username NOT IN (
SELECT b.by_user 
FROM bp_userlist b) 
and a.version="823" 

更新时间： 前删除： 用户：

uid username name location version 
1 abc  abc abcdd O 
2 abc  abc abcdd 823 
3 ddd  ddd dddd 823 

thing 

thingid username version 

1  abc  O 
2  abc  O 
1  abc  823 
2  abc  823 
3  ddd  823 
1  ddd   823 

thingfile 
thingid code version 
1  ee O 
2  eed O 
1  ee  823 
2  eddd 823 
3  fff 823 

后删除： 用户：

uid username name location version 
1 abc  abc abcdd O 
3 ddd  ddd dddd 823 

thing 

thingid username version 

1  abc  O 
2  abc  O 
3  ddd  823 
1  ddd   823 


thingfile 
thingid code version 
1  ee O 
2  eed O 
3  fff 823 

我想要那些属于thingi的记录东西和东西文件表中的东西也会被删除。是否有可能没有外键约束？我有超过10个表和许多连接不能在一个查询中工作。

Answer 1

所以你已经有了第一个查询。另外两个表需要两个查询。不过，你需要以相反的顺序执行三个查询，像这样：

DELETE t FROM thingfile t 
INNER JOIN thing a ON a.thingid = t.thingid 
        AND a.version = t.version 
WHERE a.username NOT IN (
     SELECT b.by_user 
     FROM bp_userlist b) 
    AND a.version = '823'; 


DELETE a FROM thing a 
WHERE a.username NOT IN (
     SELECT b.by_user 
     FROM bp_userlist b) 
    AND a.version = '823'; 


DELETE a FROM user a 
WHERE a.username NOT IN (
     SELECT b.by_user 
     FROM bp_userlist b) 
    AND a.version = '823'; 

这里是一个fiddle（选择“仅文本结果”，并运行该查询，在文本中看到3个结果比更容易在网格中）。

Answer 2

@RacilHilan我不会假装，这正好对应到所需的解决方案，但我举例来说，你可以从几个表中同时删除（不使用CASCADE ON DELETE）提出它...

DROP TABLE IF EXISTS user; 

CREATE TABLE user 
(user_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY 
,version INT NOT NULL); 

INSERT INTO user VALUES 
(1,0), 
(2,823), 
(3,823); 

DROP TABLE IF EXISTS thing; 

CREATE TABLE thing 
(thing_id INT NOT NULL 
,user_id INT NOT NULL 
,version INT NOT NULL 
); 

INSERT INTO thing VALUES 
(1,1,0), 
(2,1,0), 
(1,1,823), 
(2,1,823), 
(3,2,823), 
(1,2,823); 

DROP TABLE IF EXISTS thing_file; 

CREATE TABLE thing_file 
(thing_id INT NOT NULL 
,version INT NOT NULL 
,PRIMARY KEY (thing_id,version) 
); 

INSERT INTO thing_file VALUES 
(1,0), 
(2,0), 
(1,823), 
(2,823), 
(3,823); 

SELECT * FROM user; 
+---------+---------+ 
| user_id | version | 
+---------+---------+ 
|  1 |  0 | 
|  2 |  823 | 
|  3 |  823 | 
+---------+---------+ 

SELECT * FROM thing; 
+----------+---------+---------+ 
| thing_id | user_id | version | 
+----------+---------+---------+ 
|  1 |  1 |  0 | 
|  2 |  1 |  0 | 
|  1 |  1 |  823 | 
|  2 |  1 |  823 | 
|  3 |  2 |  823 | 
|  1 |  2 |  823 | 
+----------+---------+---------+ 

SELECT * FROM thing_file; 
+----------+---------+ 
| thing_id | version | 
+----------+---------+ 
|  1 |  0 | 
|  1 |  823 | 
|  2 |  0 | 
|  2 |  823 | 
|  3 |  823 | 
+----------+---------+ 

DELETE u,t,f 
    FROM user u 
    JOIN thing t 
    ON t.user_id = u.user_id 
    JOIN thing_file f 
    ON f.thing_id = t.thing_id 
    WHERE 823 IN (u.version,t.version,f.version); 
Query OK, 13 rows affected (0.00 sec) 

SELECT * FROM user; 
+---------+---------+ 
| user_id | version | 
+---------+---------+ 
|  3 |  823 | 
+---------+---------+ 
1 row in set (0.00 sec) 

SELECT * FROM thing; 
Empty set (0.00 sec) 

SELECT * FROM thing_file; 
Empty set (0.00 sec)