Question

放弃ORDER BY + LIMIT，或 JOIN，一切都是桃子。把它们放在一起，我似乎释放了海妖。谁可以解决一些问题？

DELETE table1 AS t1
FROM table1 AS t1 LEFT JOIN table2 AS t2 ON t1.id = t2.id
WHERE t2.field = 'something'
ORDER BY t1.id DESC
LIMIT 5

（Delete using aliases）

我也尝试过没有别名＆amp;放弃WHERE，无济于事。始终是语法错误“near 'ORDER BY...”。

Answer 1

来自Mysql文档：DELETE

对于多表语法，DELETE从每个tbl_name中删除满足条件的行。 在这种情况下，无法使用ORDER BY和LIMIT 。

在您的情况下，我认为这有效：

DELETE 
FROM table1
WHERE EXISTS
      ( SELECT t2.id
        FROM table2 AS t2
        WHERE t2.id = table1.id
          AND t2.field = 'something'
      ) 
ORDER BY id DESC
LIMIT 5

Answer 2

如果您确实需要这样做，可以执行以下操作

DELETE table1 
WHERE id in
      (SELECT t.id
      FROM table1 AS t INNER JOIN table2 AS t2 ON t1.id = t2.id
      WHERE t2.field = 'something' --No point in doing a LEFT JOIN because of this
      ORDER BY t1.id DESC
       LIMIT 5)

Answer 3

t1未被声明为别名。尝试t到处t1（反之亦然）。

DELETE + JOIN + ORDER BY + LIMIT =语法错误

3 个答案: