Question

对于我来说，使用wordpress wp_post表和wp_postmeta表以及wp_user表为Wordpress站点构建以下查询是一个真正的挑战。它工作得很好，但它包含了很多重复的陈述。我不确定如何简化（或者如果可以）。任何简化和消除重复的提示都将受到赞赏。

表包含如下数据：

wp_posts
 ID | post_author | post_parent | post_type    | post_title | post_date
2258  163           0             fep_message    a
2262  1             2258          fep_message    re:a
2264  163           2258          fep_message    re:a
1698  1             0             fep_message    b
1692  1             0             fep_message    c

wp_postmeta
meta_id | post_id | meta_key          | meta_value
14696     2258      _fep_participants   1
14697     2258      _fep_participants   163
9819      1698      _fep_participants   163
9820      1698      _fep_participants   1
9759      1692      _fep_participants   163
9760      1692      _fep_participants   1
9815      1692      _fep_delete_by_1    1499496054
13751     1698      _fep_delete_by_163  1501044119

wp_user
ID   | user_login 
1      myname
163    theirname

这是查询

SELECT a.*
FROM (
SELECT p.id, p.post_date, p.post_title, uf.user_login AS from_login, ut.user_login AS to_login 
FROM wp_posts AS p
    JOIN wp_postmeta pm_to
    ON  (p.id = pm_to.post_id 
    AND pm_to.meta_key = '_fep_participants' 
    AND p.post_parent = 0 
    AND pm_to.meta_value <> p.post_author)
    JOIN wp_postmeta pm_delete
    ON (p.id = pm_delete.post_id)
LEFT JOIN wp_users AS uf ON uf.ID = p.post_author 
LEFT JOIN wp_users AS ut ON ut.ID = pm_to.meta_value    
WHERE (p.post_type = 'fep_message' AND pm_delete.meta_value <> '_fep_delete_by_1' AND uf.user_login = 'myname'
OR p.post_type = 'fep_message' AND pm_delete.meta_value <> '_fep_delete_by_1' AND ut.user_login = 'myname')
AND p.post_date >= '2017-07-07 00:00:00'  
AND p.post_date <= '2017-08-12 23:59:59'
ORDER BY p.post_date
) a

UNION

SELECT b.*
FROM (
SELECT p.id, p.post_date, p.post_title, uf.user_login AS from_login, ut.user_login AS to_login 
FROM wp_posts AS p
    JOIN wp_postmeta pm_to
    ON (p.post_parent = pm_to.post_id 
    AND p.post_parent <> 0 
    AND pm_to.meta_key = '_fep_participants' 
    AND pm_to.meta_value <> p.post_author) 
    JOIN wp_postmeta pm_delete
    ON (p.id = pm_delete.post_id)
LEFT JOIN wp_users AS uf ON uf.ID = p.post_author 
LEFT JOIN wp_users AS ut ON ut.ID = pm_to.meta_value    
WHERE (p.post_type = 'fep_message' AND pm_delete.meta_value <> '_fep_delete_by_1' AND uf.user_login = 'myname'
OR p.post_type = 'fep_message' AND pm_delete.meta_value <> '_fep_delete_by_1' AND ut.user_login = 'myname')
AND p.post_date >= '2017-07-07 00:00:00'  
AND p.post_date <= '2017-08-12 23:59:59'
ORDER BY p.post_date
) b

它产生的结果是：

id     |post_date              |post_title     |from_login     |to_login    
1692    2017-07-07 11:45:03     c               myname          theirname   
1698    2017-07-08 16:28:18     b               myname          theirname   
2258    2017-08-11 23:15:10     a               theirname       myname  
2262    2017-08-12 16:48:05     re:a            myname          theirname

Answer 1

谢谢Solaflare。这样做了。这是我的简化：

SELECT p.id, p.post_date, p.post_title, uf.user_login AS from_login, ut.user_login AS to_login 
FROM wp_posts AS p
    JOIN wp_postmeta pm_to
    ON  ((p.id = pm_to.post_id 
    AND p.post_parent = 0) OR (p.post_parent = pm_to.post_id 
    AND p.post_parent <> 0)) 
    AND pm_to.meta_key = '_fep_participants' 
    AND pm_to.meta_value <> p.post_author)
    JOIN wp_postmeta pm_delete
    ON (p.id = pm_delete.post_id)
LEFT JOIN wp_users AS uf ON uf.ID = p.post_author 
LEFT JOIN wp_users AS ut ON ut.ID = pm_to.meta_value    
WHERE (p.post_type = 'fep_message' AND pm_delete.meta_value <> '_fep_delete_by_1' AND uf.user_login = 'myname'
OR p.post_type = 'fep_message' AND pm_delete.meta_value <> '_fep_delete_by_1' AND ut.user_login = 'myname')
AND p.post_date >= '2017-07-07 00:00:00'  
AND p.post_date <= '2017-08-12 23:59:59'
ORDER BY p.post_date

使我的MySQL查询更简洁

1 个答案: