回答问题

假设我想删除 10% 的行,是否有执行此操作的查询?

就像是:

DELETE FROM tbl WHERE conditions LIMIT (SELECT COUNT(*) FROM tbl WHERE conditions) * 0.1
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Answers

我会简单地返回过滤行的总数,通过 php 计算并将该值用作我的 DELETE 查询中的限制。

$query = mysql_query("SELECT COUNT(*) FROM tbl WHERE conditions");
$int = reset(mysql_fetch_array($query));
$int = round($int * 0.1);

mysql_query("DELETE FROM tbl WHERE conditions LIMIT {$int}");
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我不确定 DELETE 是否允许像这样的高级查询:

DELETE FROM (   SELECT h2.id
                FROM (  SELECT COUNT(*) AS total
                        FROM tbl
                        WHERE conditions) AS h
                JOIN (  SELECT *, @rownum := @rownum + 1 AS rownum
                        FROM tbl, (SELECT @rownum := 0) AS vars
                        WHERE conditions) AS h2
                ON '1'
                WHERE rownum < total * 0.1) AS h3
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