Question

我正在尝试将最近的10个条目保留在我的数据库中并删除旧的条目。我尝试了DELETE FROM people ORDER BY id DESC LIMIT $excess，但它刚刚删除了前10个条目。

$query = "SELECT * FROM people";
$result = mysqli_query($conn, $query);
$count = mysqli_num_rows($result);
if ($count > 10) {
    $excess = $count - 10;
    $query = "DELETE FROM people WHERE id IN(SELECT id FROM people ORDER BY id DESC LIMIT '$excess')";
    mysqli_query($conn, $query);
}

Answer 1

这样的东西？获取子查询中的十个最新ID，然后删除所有其他ID。

DELETE FROM people WHERE id NOT IN (SELECT id FROM PEOPLE ORDER BY id DESC LIMIT 10)

Answer 2

您可以使用： -

DELETE FROM `people`
WHERE id NOT IN (
  SELECT id
  FROM (
    SELECT id
    FROM `people`
    ORDER BY id DESC
    LIMIT 10
  ) 
);

此外，您的查询逻辑上不正确，您将按降序获取记录。即Latest to older，您正在删除最近的记录。请改用ASC。

Answer 3

你的逻辑到处都是，[你应该ORDER BY ASC，而不是DESC]，如果有[例如] 10,000个条目，你的查询会花费很长时间，因为你有一个{{ 1}}子句，包含9,990个条目，用于比较所有10,000到。

选择最近的10个，并删除不在的位置。

IN

Answer 4

也许找到第10个元素的ID，然后删除所有较旧的行？

删除旧数据库条目

4 个答案: