我在下面的查询中使用了union。
"SELECT * FROM (
SELECT 1 AS `table`,
`comment_post_id` AS `feed_id`,
`blog_id` AS `from_blog`,
`comment_author` AS `author`,
`comment_content_stripped` AS `feed_title`,
`comment_content` AS `post_content_s`,
`type` AS `type`,
null AS `object_type`,
`comment_date_gmt` AS `date`
FROM `wp_site_comments`
UNION
SELECT 2 AS `table`,
`post_id` AS `feed_id`,
null AS `from_blog`,
`blog_id` AS `author`,
`post_title` AS `feed_title`,
`post_content_stripped` AS `post_content_s`,
`post_type` AS `type`,
null AS `object_type`,
`post_published_gmt` AS `date`
FROM `wp_site_posts`
UNION
SELECT 3 AS `table`,
`object_id` AS `feed_id`,
`blog_id` AS `from_blog`,
`user_id` AS `author`,
null AS `feed_title`,
null AS `post_content_s`,
`type` AS `type`,
`object_type` AS `object_type`,
`date_added` AS `date`
FROM `wp_global_likes`
UNION
SELECT 4 AS `table`,
`object_id` AS `feed_id`,
null AS `from_blog`,
`user_id` AS `author`,
null AS `feed_title`,
null AS `post_content_s`,
`type` AS `type`,
`object_type` AS `object_type`,
`date_added` AS `date`
FROM `wp_global_followers`
) AS tb
ORDER BY `date` DESC"
基本上我只想选择author以逗号分隔值的行，如下所示：
例如。 $blog_ids = (23, 55, 19, 10)和$user_ids = (22, 55, 19, 40)
联合中的第一个表，author是comment_author，它是用户ID。
联合中的第二个表，author is blog_id`是一个博客ID。
联合的第三个和第四个表，author是user_id，它是user_id。
现在，我希望以某种方式将author与博客ID和用户ID区分开，以便我的查询将选择author位于$blog_ids和$user_ids的行。< / p>
我用过，
WHERE author in (" . $blog_ids . ")，它返回正确。现在我想要加入$user_id。
请注意，$blog_ids和$user_ids可能具有相同的值。
我希望你明白我的意思，我想这是我能做出的最佳解释。