Question

DELETE FROM Table1 WHERE ConditionID =？ConditionID;

DELETE FROM Table2 WHERE ConditionID=?ConditionID;

DELETE FROM Table3 WHERE ConditionID=?ConditionID;

ConditionID是Table1，Table2，Table3中的一列，而不是单独运行3次，有没有办法在单个查询中运行所有这三个（在mysql中）？

Answer 1

如果所有三个表的ConditionID相同，您应该可以使用Multiple Table Delete Syntax：

DELETE Table1, Table2, Table3
FROM   Table1
JOIN   Table2 ON (Table2.ConditionID = Table1.ConditionID)
JOIN   Table3 ON (Table3.ConditionID = Table2.ConditionID)
WHERE  Table1.ConditionID = ?;

测试用例：

CREATE TABLE Table1 (id int, ConditionID int);
CREATE TABLE Table2 (id int, ConditionID int);
CREATE TABLE Table3 (id int, ConditionID int);

INSERT INTO Table1 VALUES (1, 100);
INSERT INTO Table1 VALUES (2, 100);
INSERT INTO Table1 VALUES (3, 200);

INSERT INTO Table2 VALUES (1, 100);
INSERT INTO Table2 VALUES (2, 200);
INSERT INTO Table2 VALUES (3, 300);

INSERT INTO Table3 VALUES (1, 100);
INSERT INTO Table3 VALUES (2, 100);
INSERT INTO Table3 VALUES (3, 100);

结果：

DELETE Table1, Table2, Table3
FROM   Table1
JOIN   Table2 ON (Table2.ConditionID = Table1.ConditionID)
JOIN   Table3 ON (Table3.ConditionID = Table2.ConditionID)
WHERE  Table1.ConditionID = 100;

SELECT * FROM Table1;
+------+-------------+
| id   | ConditionID |
+------+-------------+
|    3 |         200 |
+------+-------------+
1 row in set (0.00 sec)

SELECT * FROM Table2;
+------+-------------+
| id   | ConditionID |
+------+-------------+
|    2 |         200 |
|    3 |         300 |
+------+-------------+
2 rows in set (0.00 sec)

SELECT * FROM Table3;
Empty set (0.00 sec)

Answer 2

我不知道您的架构是什么样的，但是如果您使用InnoDB或类似的表引擎并且您有外键，则可以设置条件，这些条件将导致在父条目时删除派生条目被删除。有关详细信息，请参阅http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-key-constraints.html。

Answer 3

不。 ConditionID在每个中都是独立的 - 只是因为它具有相同的名称并不意味着它是同一列。如果您完全符合名称，您将能够更好地看到它：

DELETE FROM Table1 WHERE Table1.ConditionID=?ConditionID;

DELETE FROM Table2 WHERE Table2.ConditionID=?ConditionID;

DELETE FROM Table3 WHERE Table3.ConditionID=?ConditionID;

Answer 4

您可以通过使用mysql“delete”query来删除多个表中的行。考虑到，您有两个表格配置文件和书籍。

个人资料表包含，

ID
名称

书籍表包含，

PID
书
价

您可以使用此查询

从这两个表中删除特定ID的记录

delete profile,books from profile,books where profile.id=18 and profile.id=books.pid;

在单个查询中多次删除

4 个答案: