Question

我有以下表格是sql

诊断

DiagnosisID
DiagnosisDescription

会员

MemberID
FirstName
LastName

DiagnosisCategoryMap

DiagnosisCategoryID
DiagnosisID

MemberDiagnosis

MemberID
DiagnosisID

我需要做的是找到每个会员类别中存在最低诊断ID的诊断

这是我到目前为止的sql：

SELECT MD.MemberID AS MID,
  MD.DiagnosisID AS DID,
  DM.DiagnosisCategoryID AS CID
FROM
  MemberDiagnosis MD
    INNER JOIN DiagnosisCategoryMap DM ON MD.DiagnosisID = DM.DiagnosisID

这给了我这个结果集：

> MID  DID  CID
>  1    2    2
>  1    4    3
>  3    3    3
>  3    4    3

我需要的结果集应如下所示：

> MID   DID   CID
   1     2     2
   3     3     3

我的查询中缺少什么。

我曾尝试过一个小组，但是（当然）效果不好，因为我无法正确地为小组聚合。

我正在使用SQL SERVER，这就是我可以使用的所有

Answer 1

使用MIN聚合使用GROUP BY获取每个MemberID和DiagnosisCategoryID的最小诊断ID

SELECT MD.MemberID AS MID,
  MIN(MD.DiagnosisID) AS DID,
  DM.DiagnosisCategoryID AS CID
FROM
  MemberDiagnosis MD
  INNER JOIN DiagnosisCategoryMap DM ON MD.DiagnosisID = DM.DiagnosisID
GROUP BY
    MD.MemberID,
    DM.DiagnosisCategoryID

Answer 2

将问题分解为更小的步骤。

首先，验证您是否可以使用以下内容获得每个成员的最低诊断ID：

toString(C[1,1:2])
# [1] "48.4459, 9.989"
toString(C[1,3:4])
# [1] "49.0275, 8.7539"
sort(c(toString(C[1,1:2]), toString(C[1,3:4])))
# [1] "48.4459, 9.989"  "49.0275, 8.7539"

确认无效后，请加入DiagnosisCategoryMap表...

select MemberId as MID, min(DiagnosisId) as DID
from MemberDiagnosis
group by MemberId

Answer 3

SELECT A.ID AS MID,  MIN(C.DiagnosisID) AS DID, C.DiagnosisCategoryID AS CID
FROM 
Member A INNER JOIN MemberDiagnosis B
ON A.MemberID=B.MemberID
INNER JOIN DiagnosisCategoryMap C
ON B.DiagnosisID=C.DiagnosisID
GROUP BY A.ID, C.DiagnosisCategoryID;

如何获得每个类别SQL的最低ID

3 个答案: