单个查询中的多个删除

Question

从table1删除prentionId =？条件;

DELETE FROM Table2 WHERE ConditionID=?ConditionID;

DELETE FROM Table3 WHERE ConditionID=?ConditionID;

条件ID是表1，Table2，Table3中存在的列，而不是单独运行3次，是否可以在单个查询中运行所有三个（在MySQL中）？

Answer 1

如果是 ConditionID 所有三张表都相同，您应该能够使用 多个表删除语法:

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

我不知道您的模式是什么样的，但是如果您使用InnoDB或与外国钥匙相似的表引擎，则可以设置导致派生条目时删除父条目时删除的条件。看 http://dev.mysql.com/doc/refman/5.1/en/innodb-foreign-foreign-key-constraints.html 有关此信息的更多信息。

Answer 3

没有。 ConditionID 在每个中是分开的 - 只是因为它具有相同的名称并不意味着它是同一列。如果您完全符合名字的资格，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

您只需使用MySQL“ delete” Query.consider，您就可以从多个表中删除行，这是两个表格配置文件和书籍。

个人资料表组成，

• ID
• 姓名

书桌组成，

• pid
• 书
• 价格

您可以通过使用此查询从这两个表中删除这两个表格的记录，

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