Question

我找到了答案，但它引用的是SELECT而不是DELETE，我不确定如何在这种情况下实现给定的答案。

通过下面的查询，我想删除除最后10个最新值（由id_lv定义）以外的所有值，但仅限一个用户。

DELETE FROM last_viewed
  WHERE id_lv <= (
    SELECT id_lv
    FROM (
      SELECT id_lv
      FROM last_viewed
      WHERE user_id_lv = '$user_id'
      ORDER BY id_lv DESC
      LIMIT 1 OFFSET 10
    )
  )

当我运行它时，我得到Every derived table must have its own alias

Answer 1

您必须在DELETE语句的子查询使用的派生表中使用别名：

DELETE FROM last_viewed
  WHERE id_lv <= (
    SELECT id_lv
    FROM (
      SELECT id_lv
      FROM last_viewed
      WHERE user_id_lv = '$user_id'
      ORDER BY id_lv DESC
      LIMIT 1 OFFSET 10
    ) AS t -- You need an alias here
  )

Answer 2

使用表格（FROM）<和p>的别名和别名

DELETE FROM last_viewed
  WHERE id_lv in  (
    SELECT  t.id_lv
    FROM (
      SELECT id_lv
      FROM last_viewed
      WHERE user_id_lv = '$user_id'
      ORDER BY id_lv DESC
      LIMIT  10
    ) as t
  )

mysql每个派生表必须有自己的DELETE查询别名

2 个答案: