如何改进CASE WHEN语句以在同一行返回结果

Question

目前正在从OpenEdge进度数据库处理一些SQL脚本。目前我正在尝试根据Estimated或Actual返回事件的时间。这可以通过列中的结果来识别。我得到的问题是数据的工作方式是它显示相同的EveNumber，但在两行（一个估计一个实际）。我想将这些行合并为一个。

我已经尝试了下面的代码，但这得到了两个单独的行的结果。我尝试将案例也放入Else部分，但这不起作用。以下是我的精简代码：

SELECT 

Event_0.EveNumber
, (CASE WHEN Object_0.ObjName = '818 Artwork typeset duration' THEN TemplateRunObject_0.TroValue ELSE NULL END) AS 'Actual'
, (CASE WHEN Object_0.ObjName = '818 Artwork Estimated typeset duration' THEN TemplateRunObject_0.TroValue ELSE NULL END) AS 'Estimated'

FROM 
SBS.PUB.Event Event_0
LEFT JOIN SBS.PUB.TemplateRunObject TemplateRunObject_0 ON Event_0.TemplateRunID = TemplateRunObject_0.TemplateRunID 
JOIN SBS.PUB.Object Object_0 ON TemplateRunObject_0.ObjectId = Object_0.ObjectId

原始数据布局

Evenumber             Ogjname                              TroValue
123          818 Artwork typeset duration                     15
123          818 Artwork Estimated typeset duration           30

目前结果如下：

EveNumber          Actual          Estimated
123                 15                0
123                  0                30

我希望他们如何出现

EveNumber          Actual          Estimated
123                 15                30

Answer 1

使用max()和group by

SELECT 

Event_0.EveNumber
, max((CASE WHEN Object_0.ObjName = '818 Artwork typeset duration' THEN TemplateRunObject_0.TroValue ELSE NULL END) ) AS 'Actual'
,max( (CASE WHEN Object_0.ObjName = '818 Artwork Estimated typeset duration' THEN TemplateRunObject_0.TroValue ELSE NULL END) )AS 'Estimated'

FROM 
SBS.PUB.Event Event_0
LEFT JOIN SBS.PUB.TemplateRunObject TemplateRunObject_0 ON Event_0.TemplateRunID = TemplateRunObject_0.TemplateRunID 
JOIN SBS.PUB.Object Object_0 ON TemplateRunObject_0.ObjectId = Object_0.ObjectId
group by  Event_0.EveNumber

Answer 2

它帮助你; MAX（）函数。但你应该忘记GROUP BY。

   SELECT Event_0.EveNumber
    , (MAX(CASE WHEN Object_0.ObjName = '818 Artwork typeset duration' THEN TemplateRunObject_0.TroValue ELSE NULL END)) AS 'Actual'
    , (MAX(CASE WHEN Object_0.ObjName = '818 Artwork Estimated typeset duration' THEN TemplateRunObject_0.TroValue ELSE NULL END)) AS 'Estimated'
    FROM 
    SBS.PUB.Event Event_0
    LEFT JOIN SBS.PUB.TemplateRunObject TemplateRunObject_0 ON Event_0.TemplateRunID = TemplateRunObject_0.TemplateRunID 
    JOIN SBS.PUB.Object Object_0 ON TemplateRunObject_0.ObjectId = Object_0.ObjectId
    GROUP BY Event_0.EveNumber