Question

我想查询存储在MySQL数据库中的Wordpress数据，以获得带有列的结果：

POST_ID
类别
逗号分隔的标签

预期产出：

+---------------+----------+----------------+
| post_id       | category | tags           |
|---------------+----------+----------------+
| 213           | news     | tag1,tag2,tag3 |
+---------------+----------+----------------+

以下是我的尝试：

SELECT
    p.id,
    c.name,
    GROUP_CONCAT(t.`name`)
FROM wp_posts p
JOIN wp_term_relationships cr 
    on (p.`id`=cr.`object_id`)
JOIN wp_term_taxonomy ct 
    on (ct.`term_taxonomy_id`=cr.`term_taxonomy_id` and ct.`taxonomy`='category')
JOIN wp_terms c 
    on (ct.`term_id`=c.`term_id`)
JOIN wp_term_relationships tr 
    on (p.`id`=tr.`object_id`)
JOIN wp_term_taxonomy tt 
    on (tt.`term_taxonomy_id`=tr.`term_taxonomy_id` 
   and tt.`taxonomy`='post_tag')
JOIN wp_terms t 
    on (tt.`term_id`=t.`term_id`)

因此，我得到了我想要的列，包含预期的内容，但是我只获得了一行。

我做错了什么？

Answer 1

正如评论中所指出的，我包括了一个聚合函数，但没有＆＃34; group by＆＃34;子句。

现在这似乎有效（只添加了GROUP BY行）：

SELECT
    p.id,
    p.post_name,
    c.name,
    GROUP_CONCAT(t.`name`)
FROM wp_posts p
JOIN wp_term_relationships cr
    on (p.`id`=cr.`object_id`)
JOIN wp_term_taxonomy ct
    on (ct.`term_taxonomy_id`=cr.`term_taxonomy_id`
    and ct.`taxonomy`='category')
JOIN wp_terms c on
    (ct.`term_id`=c.`term_id`)
JOIN wp_term_relationships tr
    on (p.`id`=tr.`object_id`)
JOIN wp_term_taxonomy tt
    on (tt.`term_taxonomy_id`=tr.`term_taxonomy_id`
    and tt.`taxonomy`='post_tag')
JOIN wp_terms t
    on (tt.`term_id`=t.`term_id`)
GROUP BY p.id


+---------------+----------+----------------+
| post_id       | category | tags           |
|---------------+----------+----------------+
| 213           | news     | tag1,tag2,tag3 |
+---------------+----------+----------------+
| 216           | whatever | tag2,tag3      |
+---------------+----------+----------------+

谢谢草莓！

Answer 2

这是基于 Pierre 的代码，扩展为连接多个类别，以及包含没有类别或标签的帖子。

SELECT
    p.id,
    p.post_name,
    GROUP_CONCAT(DISTINCT c.`name`) as categories,
    GROUP_CONCAT(DISTINCT t.`name`) as tags
FROM wp_posts p
LEFT JOIN wp_term_relationships cr
    on (p.`id`=cr.`object_id`)
LEFT JOIN wp_term_taxonomy ct
    on (ct.`term_taxonomy_id`=cr.`term_taxonomy_id`
    and ct.`taxonomy`='category')
LEFT JOIN wp_terms c on
    (ct.`term_id`=c.`term_id`)
LEFT JOIN wp_term_relationships tr
    on (p.`id`=tr.`object_id`)
LEFT JOIN wp_term_taxonomy tt
    on (tt.`term_taxonomy_id`=tr.`term_taxonomy_id`
    and tt.`taxonomy`='post_tag')
LEFT JOIN wp_terms t
    on (tt.`term_id`=t.`term_id`)
GROUP BY p.id

Wordpress SQL：获取帖子类别和标签

2 个答案: