Question

看起来我的问题不够明确，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一定数量的条目，每个条目都有一个评级。评级文件的评级为＆gt; 0

我想要的是获得每张专辑的平均评分（这可以通过以下查询完成）。但是，我只想要包含其文件至少给定百分比（例如75％）的专辑（等级> 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失的条款。

Answer 1

如果您的意思是平均评分，则需要HAVING avg(rating) > 0

Answer 2

试试这个

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

或

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

Answer 3

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＆lt; - 我的例子中你的百分比是50％。

Answer 4

（更新，评论后）：

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

SQL（Sqlite）GROUP BY和COUNT

4 个答案: