@Guffa的回答很好，只要指出可能用IF语句更干净就行了

select count(IIF(Position = 'Manager', 1, NULL)) as ManagerCount
from ...

SELECT COUNT(*) FROM bla WHERE Position = 'Manager'

你的意思是:

SELECT Count(*) FROM YourTable WHERE Position = 'Manager'

如果是这样，那么是的，这是可行的!

如果使用SQL 2005或更高版本，也可以使用Pivot关键字

更多信息来自Technet

SELECT *
FROM @Users
PIVOT (
    COUNT(Position)
    FOR Position
    IN (Manager, CEO, Employee)
) as p

测试数据集

DECLARE @Users TABLE (Position VARCHAR(10))
INSERT INTO @Users (Position) VALUES('Manager')
INSERT INTO @Users (Position) VALUES('Manager')
INSERT INTO @Users (Position) VALUES('Manager')
INSERT INTO @Users (Position) VALUES('CEO')
INSERT INTO @Users (Position) VALUES('Employee')
INSERT INTO @Users (Position) VALUES('Employee')
INSERT INTO @Users (Position) VALUES('Employee')
INSERT INTO @Users (Position) VALUES('Employee')
INSERT INTO @Users (Position) VALUES('Employee')
INSERT INTO @Users (Position) VALUES('Employee')

如果你不能用where子句限制查询本身，你可以使用count聚合只计算非空值的事实:

select count(case Position when 'Manager' then 1 else null end)
from ...

你也可以用类似的方式使用sum聚合:

select sum(case Position when 'Manager' then 1 else 0 end)
from ...

我认为您可以使用一个简单的WHERE子句来只选择count some记录。