CASEは、複数の値

Question

を返し、私はこのクエリを実行する場合、私は、私はこのエラーをこのクエリ

select a.Tag,a.Type, a.[Starting Date], a.[Time From 1], a.[Time To 1], 
     DATEPART(dw,CBCal.Date) as [TagderWoche], CBCal.Date, CBCal.[Customer No_], 
     Description, [POS Holiday] 
     from [ReplicationLayer].[BackPro].[CustomerBPCal] as CBCal 
CROSS APPLY 
(
    select Type,[Starting Date],[Time From 1],[Time To 1] , 
    (case 
     WHEN DATEPART(dw,CBCal.Date)=1 then (select [Time From 1] from MyTable 
               where [Valid at Monday]=1 
               and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=3 then (select [Time From 1] from MyTable 
               where [Valid at Wednesday]=1 
               and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=4 then (select [Time From 1] from MyTable 
               where [Valid at Thursday]=1 
               and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=5 then (select [Time From 1] from MyTable 
               where [Valid at Friday]=1 
               and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=6 then (select [Time From 1] from MyTable 
               where [Valid at Saturday]=1 
               and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=7 then (select [Time From 1] from MyTable 
               where [Valid at Sunday]=1 
               and [Customer No_]=CBCal.[Customer No_]) 
    end) as Tag 
    from [CustomerShopAndArrivalTime] 
) as a 
where CBCal.[Customer No_]=1 and CBCal.[POS Holiday]=0 and Date='2015-04-15' 

を取得していています： サブクエリは複数の値を返しました。サブクエリが=、！=、=のあとに続く場合、またはサブクエリが式として使用されている場合は、これは許可されません。

私はこの問題

Answer 1

あなたのサブ選択を超える1行を返すことがなぜ考えてみましょう。この

select a.Tag, 
      a.Type, 
      a.[Starting Date], 
      a.[Time From 1], 
      a.[Time To 1], 
      DATEPART(dw,CBCal.Date) as [TagderWoche], 
      CBCal.Date, 
      CBCal.[Customer No_], 
      Description,[POS Holiday] 
from [ReplicationLayer].[BackPro].[CustomerBPCal] as CBCal 
    CROSS APPLY 
    (
    select Type,[Starting Date],[Time From 1],[Time To 1] , 
    (case 
     WHEN DATEPART(dw,CBCal.Date)=1 then 
         (select top 1 [Time From 1] from MyTable where [Valid at Monday]=1 and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=3 then 
         (select top 1 [Time From 1] from MyTable where [Valid at Wednesday]=1 and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=4 then 
         (select top 1 [Time From 1] from MyTable where [Valid at Thursday]=1 and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=5 then 
         (select top 1 [Time From 1] from MyTable where [Valid at Friday]=1 and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=6 then 
         (select top 1 [Time From 1] from MyTable where [Valid at Saturday]=1 and [Customer No_]=CBCal.[Customer No_]) 
     WHEN DATEPART(dw,CBCal.Date)=7 then 
         (select top 1 [Time From 1] from MyTable where [Valid at Sunday]=1 and [Customer No_]=CBCal.[Customer No_]) 
     end) as Tag 
     from [CustomerShopAndArrivalTime] 
    ) as a 
    where CBCal.[Customer No_]=1 and CBCal.[POS Holiday]=0 and Date='2015-04-15'