Question

这是我的MySQL查询，我在此查询中遇到周问题。我不知道如何使用WHERE子句来应用IF条件。

查询：

SELECT
*,
IFNULL((SELECT ur.user_rating FROM user_rating ur 
WHERE ur.vid_id = v.id AND ur.user_id = '1000'),'NULL') AS user_rating
FROM videos v
WHERE WEEK(v.video_released_date) = WEEK(NOW())
AND  
v.`is_done` = 1
ORDER BY v.admin_listing ASC;

我想要OR（如何在where子句中应用此条件？）

IF( WEEK(v.video_released_date) = WEEK(NOW()) , WEEK(NOW()) , WEEK(NOW())-1)
=
IF( WEEK(v.video_released_date) = WEEK(NOW()) , WEEK(NOW()) , WEEK(NOW())-1)

简报

如果视频发布日期已过，且与当前周不符，则上周应用

我自己

当我像这样尝试自己时，他们会将整个数据返回给我

SELECT
*,
IFNULL((SELECT ur.user_rating FROM user_rating ur 
WHERE ur.vid_id = v.id AND ur.user_id = '1000'),'NULL') AS user_rating
FROM videos v
WHERE IF(WEEK(v.video_released_date) = WEEK(NOW()),WEEK(NOW()),WEEK(NOW())-1)
= IF(WEEK(v.video_released_date) = WEEK(NOW()),WEEK(NOW()),WEEK(NOW())-1) 
AND  
v.`is_done` = 1
ORDER BY v.admin_listing ASC;

我在这个查询中做错了什么？

Answer 1

试试这个 -

    SELECT *,
           IFNULL((SELECT ur.user_rating FROM user_rating ur 
                   WHERE ur.vid_id = v.id AND ur.user_id = '1000'),'NULL') AS user_rating
    FROM videos v
    WHERE WEEK(v.video_released_date) = IF(WEEK(v.video_released_date) = WEEK(NOW()),WEEK(NOW()),WEEK(NOW())-1) 
    AND  v.is_done = 1
    ORDER BY v.admin_listing ASC;

Answer 2

好像您通过这些IF将x与x进行比较。

x = x“始终”为真。

Answer 3

使用 CASE WHEN ELSE END 构造。您可以在文档中了解更多相关信息here。

SELECT *,
    IFNULL((SELECT ur.user_rating FROM user_rating ur 
        WHERE ur.vid_id = v.id AND ur.user_id = '1000'),'NULL') AS user_rating
    FROM videos v
    WHERE 
        WEEK(v.video_released_date) = 
            CASE WHEN WEEK(v.video_released_date) = WEEK(NOW()) 
            THEN WEEK(NOW()) ELSE WEEK(NOW())-1 END
    AND  
        v.`is_done` = 1
ORDER BY v.admin_listing ASC;

如何在此查询中使用MySql应用带有WHERE CLAUSE的IF条件

3 个答案: