sql - SQL (Sqlite) GROUP BY 和 COUNT

Question

看起来我的问题不够清楚，所以我尝试重写它：

我有一个“文件”表，其中包括“专辑”和“评级”等字段。每个专辑在文件表中都有给定数量的条目，每个条目都有一个等级。分级文件的分级 > 0。

我想要的是获得每张专辑的平均评分（这可以通过下面的查询来完成）。但是，我只想包括其文件的至少给定百分比（例如 75%）被评级的专辑（评级 > 0）

select album, avg(rating) AS avgRating
from file 
group by album 
order by avgRating DESC

有人可以帮助添加缺少的条款。

Answer 1

select
    album,
    (case when sum(rating>0)>(count(*)/2) then avg(rating) else -1 end) AS avgRating
from file 
group by album 
having avgRating >= 0
order by avgRating DESC

count(*)/2 <-- 在我的示例中，您的百分比为 50%。

Answer 2

（更新，以下评论）：

select album, avg(rating) AS avgRating
from file 
group by album 
having sum(case when rating > 0 then 1 end)*1.0 / count(*) > 0.5
order by avgRating DESC

Answer 3

如果您的意思是平均评分，您需要HAVING avg(rating) > 0

Answer 4

尝试这个

select album, avg(rating) AS avgRating from file  group by album  having avg(rating)>0 order by avgRating DESC

或者

select album, avg(rating) AS avgRating from file  group by album where rating>0 order by avgRating DESC