SQL函数按大多数热门内容排序

Question

我不知道SQL是否可以实现:我有两个表,一个是内容,每个都有一个整数ID,还有一个注释表,每个表都有一个"On"字段,表示它所在的内容.我希望按照"On"字段中有多少条评论的内容接收内容,并希望SQL能够做到.

Answer 1

SELECT   comment.on AS content_id, COUNT(comment_id) AS num_comments
FROM     comments
GROUP BY content_id
ORDER BY num_comments DESC

如果您需要内容的所有字段,您可以进行加入:

SELECT   contents.*, COUNT(comment_id) AS num_comments
FROM     contents
  LEFT JOIN comments on contents.content_id = comments.on
GROUP BY content_id
ORDER BY num_comments DESC