我正在尝试从按 spot_id 和 vote_type 分组的表中获取最大总行数,但我需要的另一个字段 (video_id) 不在该组中,所以我想这就是为什么它在结果中给出了错误的 video_id放。我的查询有什么问题?
查询:
SELECT
max(total_votes) as total, spot_id, vote_type, video_id
FROM
(
SELECT
count(*) as total_votes, spot_id, video_id, vote_type
FROM
spot_video_votes
GROUP BY
spot_id, video_id, vote_type
) AS t
GROUP BY
spot_id, vote_type
子查询结果:
total_votes, spot_id, video_id, vote_type
'1','1','2','OWN'
'1','1','3','OWN'
'4','1','4','OWN' -- should pick this
'1','2','3','FAIL'
'2','2','3','OWN' -- this
'2','2','4','FAIL' -- and this
'1','2','4','OWN'
实际结果:
total, spot_id, video_id, vote_type
'4','1','2','OWN'
'2','2','3','FAIL'
'2','2','3','OWN'
预期结果:
total, spot_id, video_id, vote_type
'4','1','4','OWN'
'2','2','4','FAIL'
'2','2','3','OWN'
最佳答案
如果不按 video_id 字段分组,您会从相应的分组字段中收到一个仲裁值。
一个选项是将 max 查询的结果加入到自身中——像这样:
SELECT t1.total_votes as total, t1.spot_id, t1.vote_type, t1.video_id
FROM
(
SELECT count(*) as total_votes, spot_id, video_id, vote_type
FROM spot_video_votes
GROUP BY spot_id, video_id, vote_type
) AS t1 JOIN
(
SELECT max(total_votes) as max_total_votes, spot_id, vote_type, video_id
FROM
(
SELECT count(*) as total_votes, spot_id, video_id, vote_type
FROM spot_video_votes
GROUP BY spot_id, video_id, vote_type
) AS t
GROUP BY spot_id, vote_type
) t2 ON t1.total_votes = t2.max_total_votes
AND t1.spot_id = t2.spot_id
AND t1.vote_type = t2.vote_type
关于mysql - 带有 GROUP BY 的 SQL MAX 得到错误的非分组字段,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17079051/