单个查询中多次删除

Question

从表1中删除WHERE Con​​ditionID =？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全部三个（在mysql中）？

Answer 1

如果ConditionID三个表的都相同，则应该可以使用“ 多表删除语法”：

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)