聚合函数的小问题

Question

我的聚合函数存在一个小问题，我无法解决。 我必须为我的数据库中的每个代表计算客户数量 - 我可以做到这一点 - 我的第二部分是我必须只显示拥有最多客户的代表。

到目前为止，我有;

SELECT Rep.RepNum, Count(Customer.RepNum) AS [CustomerCount]

FROM Rep INNER JOIN Customer ON Rep.RepNum = Customer.Repnum

GROUP BY Rep.RepNum

我知道我可能不得不使用嵌套查询来解决这个问题，但我不确定如何解决这个问题。几乎每小时都在和我作战，任何帮助都会非常感激。

Answer 1

尝试：

 SELECT TOP 1 Rep.RepNum,
   Count(Customer.RepNum) AS [CustomerCount]
FROM Rep
INNER JOIN Customer ON Rep.RepNum = Customer.Repnum
GROUP BY Rep.RepNum
ORDER BY COUNT(Customer.RepNum) DESC

Answer 2

也许会这样做：

SELECT Rep.RepNum, Count(Customer.RepNum) AS [CustomerCount]
FROM Rep INNER JOIN Customer ON Rep.RepNum = Customer.Repnum
GROUP BY Rep.RepNum
HAVING Count(Customer.RepNum) = ( 
       Select max([CustomerCount]) 
       FROM (SELECT Rep.RepNum, 
             Count(Customer.RepNum) AS [CustomerCount]
             FROM Rep INNER JOIN Customer ON Rep.RepNum = Customer.Repnum
             GROUP BY Rep.RepNum));