sql - 自加入带来太多记录

Question

我有这个查询来表达一组业务规则。为了获得我需要的信息，我尝试加入表本身，但这会带回比表中实际更多的记录。以下是我尝试过的查询。我究竟做错了什么？

SELECT DISTINCT a.rep_id, a.rep_name, count(*) AS 'Single Practitioner'
FROM [SE_Violation_Detection] a inner join [SE_Violation_Detection] b 
ON a.rep_id = b.rep_id and a.hcp_cid = b.hcp_cid
group by a.rep_id, a.rep_name
having count(*) >= 2

Answer 1

您可以使用 having 子句来完成此操作：

select a, b, count(*) c
from etc
group by a, b
having count(*) >= some number

Answer 2

我想出了一种更简单的方法来获取其中一个查询所需的信息。上面那个还是错的。

--Rep violation for different HCP more than 5 times 
select distinct rep_id,rep_name,count(distinct hcp_cid) 
AS 'Multiple Practitioners' 
from dbo.SE_Violation_Detection
group by rep_id,rep_name 
having count(distinct hcp_cid)>4 
order by count(distinct hcp_cid)