Sql 大小写返回多个值

我有这个疑问

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'

如果运行此查询，则会出现以下错误： 子查询返回了多个值。当子查询在=、！=、=或者当子查询用作表达式时

---

如何解决此问题

您可以像这样使用函数max、min或top

    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'

---

考虑为什么子选择可能返回超过1行。在这种情况下，您想做什么？这是案例问题，我只想在案例中运行一个查询。我认为CASECase中不止一个SELECT ar运行有另一种语法，即使用一次值，然后使用多个case值：case value WHEN 1 then。。。当2时，那么…我希望有`如果DATEPARTdw，CBCal.Date=1'，那么这个查询`从MyTable中选择[Time From 1]，其中[Valid at Monday]=1和[Customer No_]=CBCal.[Customer No_uz]'，等等…它不是由该案例引起的。如果将整个CASE表达式替换为MyTable中的[Time From 1]，其中[Valid at Monday]=1和[Customer No.]=CBCal.[Customer No.]。也就是说，在查询的某个点上，您需要提供一个生成值的表达式。您已经编写了一些返回多个值的内容。系统不知道该怎么做。我希望所有的数据，而不仅仅是one@kaja只允许所有记录返回分隔的行。@Kaja，当大小写标量表达式返回多行时，是否希望在最终结果中增加行？否则，您将需要返回一个带分隔符的值列表，如Mukesh建议的。