Question

我有2张桌子 - 帖子和帖子。

posts
ID   title   category  post_status  post_type    

1    ABC      cat-1    Publish      Store
2    DEF      cat-2    Publish      Store
3    GHI      cat-3    Publish      Store
4    JKL      cat-2    Publish      Store
5    XYZ      cat-5    Draft        Store
6    MNO      cat-9    Publish      Article

和

postmeta
meta_id post_id  meta_key    meta_value

109       1       city          1
110       1       featured      h
111       2       city          1,2
112       2       featured      both
113       3       city          2,3
114       3       featured      both
115       4       city          1
116       4       featured      n
117       5       city          1,4
118       5       featured      h 
119       6       city          1
120       6       featured      h

我正在尝试运行一个查询，它会给我一个包含以下条件的帖子列表：

对城市的价值为1 AND
其特征值为h或两者都是AND
，其帖子状态为Publish AND
，其帖子类型为商店
按标题排序

我正在尝试的查询是

SELECT DISTINCT posts.ID , posts.*, postmeta.*
            FROM posts, postmeta
            WHERE posts.ID = postmeta.post_id
            AND (postmeta.meta_value  = 'h' OR postmeta.meta_value = 'both') 

AND (postmeta.meta_key = 'post_city_id' AND (postmeta.meta_value LIKE '%,1,%' OR postmeta.meta_value LIKE '%1,%'  OR postmeta.meta_value LIKE '%,1%' OR postmeta.meta_value LIKE '%1%'))

            AND posts.post_status = 'Publish' 
            AND posts.post_type = 'Store'

            ORDER BY (SELECT postmeta.meta_value from postmeta where (posts.ID = postmeta.post_id) and postmeta.meta_key LIKE '%home_featured_type%') asc, posts.post_title LIMIT 0,6

正确的返回值是ID 1和2，即abc和def。但我得到空洞的结果。我无法弄清楚它在哪里分崩离析。如何解决这个问题？

Answer 1

这是一个固定的查询，但我仍然不明白神秘的ORDER BY (SELECT)东西。

http://sqlfiddle.com/#!2/5ce5a/19

SELECT DISTINCT posts.ID , posts.*, postmeta_city.*, postmeta_featured.*

FROM       posts

INNER JOIN postmeta AS postmeta_city
     ON     postmeta_city.post_id = posts.ID
    AND     postmeta_city.meta_key = 'city'
    AND (   postmeta_city.meta_value LIKE '%,1,%'
         OR postmeta_city.meta_value LIKE '%1,%'
         OR postmeta_city.meta_value LIKE '%,1%'
         OR postmeta_city.meta_value LIKE '%1%'
        )
INNER JOIN postmeta AS postmeta_featured
     ON     postmeta_featured.post_id = posts.ID
    AND     postmeta_featured.meta_key = 'featured'
    AND (   postmeta_featured.meta_value = 'h'
         OR postmeta_featured.meta_value = 'both'
        )

WHERE posts.post_status = 'Publish' 
  AND posts.post_type = 'Store'

ORDER BY (
    SELECT postmeta.meta_value
    FROM postmeta
    WHERE ( posts.ID = postmeta.post_id )
      AND postmeta.meta_key LIKE '%home_featured_type%'
  ) asc,
  posts.title

LIMIT 0,6;
;

更新了其他人的想法，请提升他们：

http://sqlfiddle.com/#!2/5ce5a/33

SELECT DISTINCT posts.ID , posts.*, postmeta_city.*, postmeta_featured.*

FROM       posts

INNER JOIN postmeta AS postmeta_city
     ON postmeta_city.post_id = posts.ID
    AND postmeta_city.meta_key = 'city'
    AND FIND_IN_SET('1', postmeta_city.meta_value)

INNER JOIN postmeta AS postmeta_featured
     ON postmeta_featured.post_id = posts.ID
    AND postmeta_featured.meta_key = 'featured'
    AND postmeta_featured.meta_value IN ('h','both')

WHERE posts.post_status = 'Publish' 
  AND posts.post_type = 'Store'

ORDER BY (
    SELECT postmeta.meta_value
    FROM postmeta
    WHERE ( posts.ID = postmeta.post_id )
      AND postmeta.meta_key LIKE '%home_featured_type%'
  ) asc,
  posts.title

LIMIT 0,6;
;

Answer 2

您获得一个空结果集，因为您AND meta_value列val = '1' AND val = 'both'，因此它必须同时等于两个值，这是不可能的。像OR这样的东西总是返回false，没有任何行会加入。相反，您必须在条件之间使用HAVING：city - ＆gt; 1和特色 - ＆gt; H /两。

由于帖子必须包含两个城市 - ＆gt; 1和特色 - ＆gt; h / both（不是跨列而是跨多行），你需要一个GROUP BY子句和LIKE一起来确保每个帖子连接两行，满足两个条件......不是一个或另一个。

此外，检查1的存在是否有很多SELECT * FROM posts a INNER JOIN postmeta b ON a.ID = b.post_id AND ( (b.meta_key = 'city' AND FIND_IN_SET('1', b.meta_value) > 0) OR (b.meta_key = 'featured' AND b.meta_value IN ('h', 'both')) ) WHERE a.post_status = 'Publish' AND a.post_type = 'Store' GROUP BY a.ID HAVING COUNT(*) = 2 ORDER BY a.title。您可以改为使用FIND_IN_SET：

{{1}}

Answer 3

试试这个：

SELECT DISTINCT posts.ID , posts.*, postmeta.*
            FROM posts AS p INNER JOIN postmeta AS pm
            WHERE p.ID = pm.post_id
            AND (pm.meta_value  in ('h','both') 

AND (pm.meta_key = 'city' AND 
(pm.meta_value LIKE '%,1,%' OR pm.meta_value LIKE '%1,%'  OR pm.meta_value LIKE '%,1%' OR pm.meta_value LIKE '%1%'))

            AND posts.post_status = 'Publish' 
            AND posts.post_type = 'Store'

            ORDER BY p.title LIMIT 0,6

由于您只想按标题排序，因此无需在'order by'子句中编写任何查询。

MySQL查询返回空

3 个答案: