mysql - 用于删除的 db_query 在 PHP 代码中不起作用，但直接在 mysql 中执行正常

Question

当我在网站上运行此脚本时，即使输出显示查询成功(它暂时输出写出的删除查询)，它也不会删除任何行。当我直接在 mysql 中运行查询时，它确实删除了行。

    if (db_query("DELETE FROM {watchdog} WHERE ((type = 'user' AND message IN ('Session opened for %name.', 'Session closed for %name.', 'New user: %name (%email).')) OR type = 'access denied' OR (type = 'smtp' AND message = 'Sending mail to: @to')) AND hostname = '%s'", array($hostname)))
    {
      echo "<br />DELETE FROM watchdog WHERE ((type = 'user' AND message IN ('Session opened for %name.', 'Session closed for %name.', 'New user: %name (%email).')) OR type = 'access denied' OR (type = 'smtp' AND message = 'Sending mail to: @to')) AND hostname = '$hostname'";
    }
    else
    {
      echo "<br />could not delete $hostname ";
    }

屏幕上或任何日志中都没有错误消息。

Answer 1

事实证明我必须转义百分号

 ('Session opened for %name.', 'Session closed for %name.', 'New user: %name (%email).')) 

变成了

 ('Session opened for %%name.', 'Session closed for %%name.', 'New user: %%name (%%email).'))