Question

我有一个WordPress帖子表和一个postmeta表。对于那些不熟悉结构的人来说，他们是：

wp_postmeta表：

+------------+---------------------+------+-----+---------+----------------+
| Field      | Type                | Null | Key | Default | Extra          |
+------------+---------------------+------+-----+---------+----------------+
| meta_id    | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| post_id    | bigint(20) unsigned | NO   | MUL | 0       |                |
| meta_key   | varchar(255)        | YES  | MUL | NULL    |                |
| meta_value | longtext            | YES  |     | NULL    |                |
+------------+---------------------+------+-----+---------+----------------+

wp_postmeta的示例数据：

+---------+---------+---------------------+-------------+
| meta_id | post_id | meta_key            | meta_value  |
+---------+---------+---------------------+-------------+
|   20399 |     267 | youtube_video_id_zh | xdr4lzJ4pYU |
|   20403 |     267 | video_view_count    | 3           |
|   21855 |     278 | video_view_count    | 13          |
|   21858 |     278 | youtube_video_id_zh | 5yS5cmA4-rg |
|   26042 |     354 | video_view_count    | 13          |
|   26138 |     354 | youtube_video_id_zh | iXWMThIohcM |
+---------+---------+---------------------+-------------+

wp_posts表:( ID是帖子ID）

+------------------------+---------------------+------+-----+----------+----------------+
| Field                  | Type                | Null | Key | Default  | Extra          |
+------------------------+---------------------+------+-----+----------+----------------+
| ID                     | bigint(20) unsigned | NO   | PRI | NULL     | auto_increment |
| (other fields skipped) |                     |      |     |          |                |
+------------------------+---------------------+------+-----+----------+----------------+

每个WordPress帖子都可以在wp_postmeta中包含多个元行。我需要根据SELECT的值wp_posts在ORDER BY表格上meta_value进行meta_key，但仅当video_view_count为JOIN时才需要WHERE我可以获得具有最高/最低视图数的帖子。我无法使用简单的meta_key，因为{{1}}条件需要检查其他类型的{{1}}。

这是否可以在（我的）SQL中使用？

Answer 1

首先我们可以从wp_posts加入post meta并选择发布数据。请注意，由于连接，我们使用group by。

SELECT wp_posts.* FROM
wp_posts
LEFT JOIN wp_postmeta ON (wp_posts.id = wp_postmeta.post_id)
GROUP BY wp_posts.id

从这里我们只能加入适当的postmeta并使用它来订购：

SELECT wp_posts.*, wp_postmeta.meta_value AS video_count FROM
wp_posts
LEFT JOIN wp_postmeta ON (wp_posts.id = wp_postmeta.post_id AND wp_postmeta.meta_key = 'video_view_count')
GROUP BY wp_posts.id
ORDER BY wp_postmeta.meta_value

（请注意，如果meta_keys不是每个帖子都重复，则group by实际上并不是必需的）

评论后编辑，在另一个帖子上添加了排除：

SELECT wp_posts.*, wp_postmeta.meta_value AS video_count 
FROM wp_posts
INNER JOIN wp_postmeta ex ON (wp_posts.id = ex.post_id  AND wp_ex.meta_key = 'video_duration' AND CAST(wp_ex.meta_value AS CHAR) >= '240')
LEFT JOIN wp_postmeta ON (wp_posts.id = wp_postmeta.post_id AND wp_postmeta.meta_key = 'video_view_count')
GROUP BY wp_posts.id
ORDER BY wp_postmeta.meta_value

SQL ORDER BY带有来自另一个表的条件结果

1 个答案: