根据子查询计数返回MYSQL结果？

Question

有没有办法调整以下MYSQL查询，以便它只显示视频计数大于0的结果？我尝试了以下但是它无法识别

  

VIDEO_COUNT

SELECT channels.*, 
(SELECT COUNT(*) FROM videos WHERE videos.video_publisher_id = channels.channel_id) as `video_count` 
FROM channels 
WHERE  channel_active = 1
AND video_count > 0
AND channel_thumbnail IS NOT NULL
ORDER BY channel_subscribers DESC

Answer 1

将子查询从SELECT子句移动到FROM子句。内连接保证匹配。

SELECT c.*, v.video_count
FROM channels c
JOIN
(
  SELECT video_publisher_id, COUNT(*) AS video_count
  FROM videos 
  GROUP BY video_publisher_id
) v ON v.video_publisher_id = c.channel_id
WHERE c.channel_active = 1
  AND c.channel_thumbnail IS NOT NULL
ORDER BY c.channel_subscribers DESC;

Answer 2

对于按子查询结果或聚合函数值过滤，您可以使用HAVING。您在WHERE子句中有错误，因为MySQL不知道WHERE

中的此列

SELECT channels.*, 
(SELECT COUNT(*) FROM videos WHERE videos.video_publisher_id = channels.channel_id) as `video_count` 
FROM channels 
WHERE  channel_active = 1
AND channel_thumbnail IS NOT NULL
HAVING video_count > 0
ORDER BY channel_subscribers DESC

或者：

SELECT channels.*, COUNT(*) AS video_count
FROM channels 
INNER JOIN videos 
ON videos.video_publisher_id = channels.channel_id
WHERE  channel_active = 1
AND channel_thumbnail IS NOT NULL
GROUP BY channels.channel_id
ORDER BY channel_subscribers DESC

Answer 3

也许这会对你有帮助。

SELECT channels.*,video_count.count
FROM channels 
left join (SELECT channel_id,COUNT(*) count FROM videos) as `video_count` on video_count.video_publisher_id = channels.channel_id
WHERE  channel_active = 1
AND video_count.count > 0
AND channel_thumbnail IS NOT NULL
ORDER BY channel_subscribers DESC