Sql 计算百分比是与计数并列的最佳方式
我有下面的查询,我试图计算一个百分比列,但计算不正确,每行显示100,这显然是不正确的 我做错了什么?我见过很多用不同方法计算百分比的例子,我想知道这里最好的方法是什么Sql 计算百分比是与计数并列的最佳方式,sql,sql-server,sql-server-2016,Sql,Sql Server,Sql Server 2016,我有下面的查询,我试图计算一个百分比列,但计算不正确,每行显示100,这显然是不正确的 我做错了什么?我见过很多用不同方法计算百分比的例子,我想知道这里最好的方法是什么 Select DrugName, Occurrences, (Occurrences / sum(Occurrences)) * 100 as Percentage from ( select D.DrugName, count(*) as Occurrences from Visit V Inner Join Dru
Select
DrugName,
Occurrences,
(Occurrences / sum(Occurrences)) * 100 as Percentage
from
(
select
D.DrugName,
count(*) as Occurrences
from
Visit V
Inner Join Drug D on
V.DrugID = D.DrugID
where
StartDate >='01 Oct 2016' and
EndDate < '01 Jan 2017'
group by
D.DrugName
) a
group by
DrugName,
最好的方法是使用窗口函数:
select D.DrugName,
count(*) as Occurrences,
count(*) * 100.0 / sum(count(*)) over ()
from Visit V Inner Join
Drug D
on V.DrugID = D.DrugID
where StartDate >= '2016-10-01' and
EndDate < '2017-01-01'
group by D.DrugName;
谢谢你,但不幸的是,这也不起作用。每行返回0.024390243902。感谢Gordon,将1.0更改为100.0为我做到了这一点。正如约翰在下面建议的那样。