SQLエイリアスが認識されない

Question

質問を修正するのを手伝ってください。ここで、別名「startDate」は識別されません。

SELECT TOP 1 a.[ID]       
    ,b.[Name] 
    ,a.[VName] 
    ,a.[StartKM] 
    ,a.[RecurringKM] 
    ,dateadd (day,-(120000 - a.[StartKM])/80,GETDATE())as startDate 
    ,dateadd(day,(a.[RecurringKM]/80),[startDate])as [DueDate] 
FROM MaintenanceEventInstance AS a 
INNER JOIN MaintenanceEventDescriptor AS b ON a.ID=b.ID 
WHERE a.VName='test' AND a.CompletedDate IS NULL AND 
    a.ReType='4' 
order by [DueDate] asc 

ご協力いただければ幸いです。

Answer 1

あなたはSELECT句で別名を使用することはできません

SELECT TOP 1 a.[ID] 
      ,b.[Name] 
      ,a.[VName] 
      ,a.[StartKM] 
      ,a.[RecurringKM] 
      ,dateadd (day,-(120000 - a.[StartKM])/80,GETDATE())as startDate 
      ,dateadd(day,(a.[RecurringKM]/80),dateadd (day,-(120000 - a.[StartKM])/80,GETDATE()))as [DueDate] 
FROM MaintenanceEventInstance AS a 
INNER JOIN MaintenanceEventDescriptor AS b ON a.ID=b.ID 
WHERE a.VName='test' AND a.CompletedDate IS NULL AND 
    a.ReType='4' order by [DueDate] as 

Answer 2

、代わりにそこに式を追加し、同じ選択に列の別名を使用することはできません。これを代わりに試してみてください：

SELECT TOP 1 a.[ID] 
      ,b.[Name] 
      ,a.[VName] 
      ,a.[StartKM] 
      ,a.[RecurringKM] 
      ,x.startDate 
      ,dateadd(day,(a.[RecurringKM]/80),x.[startDate])as [DueDate] 
FROM MaintenanceEventInstance AS a 
INNER JOIN MaintenanceEventDescriptor AS b ON a.ID=b.ID 
CROSS APPLY (SELECT dateadd (day,-(120000 - a.[StartKM])/80,GETDATE())) AS x(startDate) 
WHERE a.VName='test' AND a.CompletedDate IS NULL AND 
     a.ReType='4' order by [DueDate] asc