Question

我有一个包含以下列的表：

SignatureID
PatientID
PatientVisitID
TreatAuthDate
HIPAADate
DrugTestDate

现在我有以下Select语句：

SELECT *
FROM tblSignature
WHERE PatientID = 12345

此select语句返回8行。我需要完成的是获得MAX TreatAuthDate - 并且使用MAX TreatAuthDate我需要PatientVisitID。然后我需要HipaaDate和DrugTestDate的相同类型的信息。我怎么能这样做？

Answer 1

SELECT  TOP 1 *
FROM    tblSignature 
WHERE   PatientID = 12345
ORDER BY
        TreatAuthDate DESC

要获得“last”的不同定义的最后三个结果，请使用：

SELECT  *
FROM    (
        SELECT  TOP 1 'LastThreatAuth' AS which, ts.*
        FROM    tblSignature ts
        WHERE   PatientID = 12345
        ORDER BY
                TreatAuthDate DESC
        ) SrcTreatAuth 
UNION ALL
SELECT  *
FROM    (
        SELECT  TOP 1 'LastHIPAA' AS which, ts.*
        FROM    tblSignature ts
        WHERE   PatientID = 12345
        ORDER BY
                HIPAADate DESC
        ) SrcHIPAA
UNION ALL
SELECT  *
FROM    (
        SELECT  TOP 1 'LastDrugTest' AS which, ts.*
        FROM    tblSignature ts
        WHERE   PatientID = 12345
        ORDER BY
                DrugTestDate DESC
        ) SrcDrugTest

Answer 2

SELECT  patientid, max(Treatauthdate), max (HippaDAte) , max (DrugTestDate)
FROM tblSignature
WHERE PatientID = 12345
group by patientid

注意在这种情况下你不能要求签名，因为你不会过滤掉任何记录（我假设签名是你的PK）。为了获得每个患者每个日期的最大值，可能它们各自位于表的不同行上，因此不会具有相同的签名。

要获得每种类型的访问日期可能会更加困难，因为每个类型可能是单独的访问。尝试像

这样的东西

select a.patientid, Treatvisitdate, Treatauthdate,Hippavisitdate, HippaDate, DrugTestvisitdate, 
DrugTestDate
(SELECT  patientid, patientvisitdate as Treatvisitdate, max(Treatauthdate) as Treatauthdate
FROM tblSignature
WHERE PatientID = 12345
group by patientid,patientvisitdate)a
join
(SELECT  patientid, patientvisitdate as Hippavisitdate, max(HippaDate) as HippaDate
FROM tblSignature
WHERE PatientID = 12345
group by patientid,patientvisitdate) b on a.patientid = b.patientid
join
(SELECT  patientid, patientvisitdate as DrugTestvisitdate, max(DrugTestDate) as DrugTestDate
FROM tblSignature
WHERE PatientID = 12345
group by patientid,patientvisitdate) c on a.patientid = c.patientid

如果某些日期可能不在那里，你可能需要左联接。

使用max时如何选择整行？

2 个答案: