Question

我有一个简单的TSQL查询：

SELECT dbo.tblHospEpisode.PATNT_PASID, [Pat_Given]+' '+[Pat_Family] AS Name, dbo.tblPhysiology.Pregnant, dbo.tblCritCareAdmit.CCDateAdmit, dbo.tblCritCareAdmit.CCDateDis, dbo.tblCritCareAdmit.CCOutcome 
From dbo.tblPhysiology, dbo.tblCritCareAdmit, dbo.tblHospEpisode,  dbo.tblDemographic
WHERE dbo.tblPhysiology.CC_ID=dbo.tblCritCareAdmit.CC_ID
AND dbo.tblCritCareAdmit.HSPEP_ID = dbo.tblHospEpisode.HSPEP_ID
AND dbo.tblHospEpisode.PATNT_PASID = dbo.tblDemographic.PATNT_PASID
AND dbo.tblPhysiology.Pregnant != 2

问题是某些字段返回需要映射到字符串的数字（数据库中没有映射。例如，怀孕代码1 =“当前怀孕”。我希望查询返回String而不是而不是代码。我不知道该怎么做？

Answer 1

您想使用案例陈述：

SELECT he.PATNT_PASID, [Pat_Given]+' '+[Pat_Family] AS Name,
       p.Pregnant, cca.CCDateAdmit, cca.CCDateDis, cca.CCOutcome,
       (case when p.Pregnant = 1 then 'Currently Pregnant'
             . . . 
             else '???'
        end) as PregString
From dbo.tblPhysiology p
     dbo.tblCritCareAdmit cca
     on p.CC_ID = cca.CC_ID join
     dbo.tblHospEpisode he
     on cca.HSPEP_ID = he.HSPEP_ID join
     dbo.tblDemographic d
     on he.PATNT_PASID = d.PATNT_PASID
WHERE p.Pregnant <> 2;

我还为查询使用了表别名来简化查询，并将join更改为使用on子句的显式连接。

Answer 2

您可以使用CASE表达式，如下所示：

select 
    case code
        when 1 then 'Currently pregnant'
        when 2 then 'Not Pregnant'
        when 3 then 'Gave Birth'
    end CodeDescription
from
    YourTable

将字段代码映射到SQL查询中的字符串

2 个答案: