MySQL从多个表中删除行

Question

这是正确的方法吗？

DELETE t1, t2, t3, t4 FROM 
  table1 as t1 
  INNER JOIN  table2 as t2 on t1.id = t2.id
  INNER JOIN  table3 as t3 on t1.id=t3.id
  INNER JOIN  table4 as t4 on t1.id=t4.id
  WHERE  t1.username='%s' AND t1.id='%s'

Answer 1

对,那是正确的.它在这里工作正常:

CREATE TABLE table1 (id int, username nvarchar(30));
CREATE TABLE table2 (id int);
CREATE TABLE table3 (id int);
CREATE TABLE table4 (id int);

INSERT INTO table1 VALUES (1, 'Foo'),(2, 'Bar');
INSERT INTO table2 VALUES (1),(2);
INSERT INTO table3 VALUES (1),(2);
INSERT INTO table4 VALUES (1),(2);

SELECT COUNT(*) FROM table1;
2
SELECT COUNT(*) FROM table2;
2
SELECT COUNT(*) FROM table3;
2
SELECT COUNT(*) FROM table4;
2

DELETE t1, t2, t3, t4 FROM
  table1 as t1
  INNER JOIN  table2 as t2 on t1.id = t2.id
  INNER JOIN  table3 as t3 on t1.id=t3.id
  INNER JOIN  table4 as t4 on t1.id=t4.id
  WHERE  t1.username='Foo' AND t1.id='1';

SELECT COUNT(*) FROM table1;
1
SELECT COUNT(*) FROM table2;
1
SELECT COUNT(*) FROM table3;
1
SELECT COUNT(*) FROM table4;
1

如果它不适合您,也许您可​​以修改此示例以显示您遇到的问题.

Answer 2

一个简单的方法是先把它写成一个查询：

SELECT * FROM 
        table1 as t1 
        INNER JOIN  table2 as t2 on t1.id = t2.id
        INNER JOIN  table3 as t3 on t1.id=t3.id
        INNER JOIN  table4 as t4 on t1.id=t4.id
        WHERE  t1.username='%s' AND t1.id='%s'

如果您得到预期的结果，只需将 *Select ** 替换为 Delete 和您的表名。那么就会变成：

Delete t1, t2, t3, t4 From table1 as t1 
        INNER JOIN  table2 as t2 on t1.id = t2.id
        INNER JOIN  table3 as t3 on t1.id=t3.id
        INNER JOIN  table4 as t4 on t1.id=t4.id
        WHERE  t1.username='%s' AND t1.id='%s'