Sql：从（选择...）中选择计数（*）

Question

我有一个带有分组的 sql select 命令，我想获取总行数。我该如何实现这一目标？

我的sql命令：

select p.UserName, p.FirstName + ' ' + p.LastName as [FullName]
 ,count(b.billid) as [Count], sum(b.PercentRials) as [Sum] from Bills b
inner join UserProfiles p on b.PayerUserName=p.UserName
 where b.Successful=1
 group by p.UserName, p.FirstName + ' ' + p.LastName

我尝试过这些但没有运气：

select count(*) from (select ...)

和

select count(select ...)

编辑

这是我想要运行的完整 sql 语句：

select count(*) from (    select p.UserName, p.FirstName + ' ' + p.LastName as [FullName]
 ,count(b.billid) as [Count], sum(b.PercentRials) as [Sum] from Bills b
inner join UserProfiles p on b.PayerUserName=p.UserName
 where b.Successful=1
 group by p.UserName, p.FirstName + ' ' + p.LastName)

我在最后一行收到此错误：

Incorrect syntax near ')'.

Answer 1

SELECT COUNT(*)
FROM 
(
select p.UserName, p.FirstName + ' ' + p.LastName as [FullName]
 ,count(b.billid) as [Count], sum(b.PercentRials) as [Sum] from Bills b
inner join UserProfiles p on b.PayerUserName=p.UserName
 where b.Successful=1
 group by p.UserName, p.FirstName + ' ' + p.LastName   --<-- Removed the extra comma here
) A  --<-- Use an Alias here

正如我从你所展示的尝试中所预期的那样，你缺少一个别名

select count(*) 
from (select ...) Q  --<-- This sub-query in From clause needs an Alias 

编辑

如果您只需要知道此查询返回的行，并且无论如何都在代码中的某个位置执行此查询，您可以简单地使用@@ROWCOUNT函数。就像是....

SELECT ......     --<-- Your Query

SELECT @@ROWCOUNT    --<-- This will return the number of rows returned 
                       -- by the previous query