为什么此查询忽略 WHERE 子句？答案

【问题标题】：Why is this query ignoring the WHERE clause?为什么此查询忽略 WHERE 子句？
【发布时间】：2014-02-22 08:38:09
【问题描述】：

这让我快疯了。

我的查询忽略了 WHERE 子句，只输出所有结果。

我知道它仍在读取脚本，因为当我将脚本更改为荒谬的内容时，例如 WHERE user=xxx is throws back an error。

帮助？

$data = mysql_query(
        "SELECT 

        tbl_messages.id as msgID, 
        tbl_messages.from_user as msgFROM,
        tbl_messages.to_user as msgTO, 
        tbl_messages.the_message as msgMESSAGE, 
        tbl_messages.status as msgSTATUS, 
        tbl_messages.date as msgDATE, 
        tbl_messages.subject as msgSUBJECT,

        tbl_users.id as usrID, 
        tbl_users.name as usrNAME,

        tbl_photos.profile as photosPROFILE,
        tbl_photos.photo_link as photoLINK,
        tbl_photos.default_photo as photoDEFAULT  

        FROM tbl_messages 
        LEFT JOIN tbl_users 
        ON tbl_messages.from_user = tbl_users.id 

        LEFT JOIN tbl_photos ON tbl_photos.profile = tbl_users.id 

        WHERE tbl_messages.to_user = 65 AND tbl_photos.default_photo IS NULL OR tbl_photos.default_photo = '1'
        ORDER BY status DESC")

【问题讨论】：

标签： where

【解决方案1】：

这只是一个猜测，但您可能需要在 WHERE 子句的某些部分加上括号；正如所写，它可能对所有行都评估为true。

WHERE tbl_messages.to_user = 65
    AND (tbl_photos.default_photo IS NULL OR tbl_photos.default_photo = '1')

【讨论】：

等等，不——拿着电话。你是对的！我误会你了。

【解决方案2】：

我觉得你也需要这样的：

WHERE tbl_messages.to_user = 65 
AND tbl_photos.default_photo ='NULL' OR tbl_photos.default_photo = 1
ORDER BY status DESC

或者像这样：

WHERE tbl_messages.to_user = 65 
AND tbl_photos.default_photo ='NULL' OR tbl_photos.default_photo = '1'
ORDER BY status DESC

【讨论】：