Sql 在WHERE子句中将字符串值用作布尔值

是否可以在where子句中将值用作类型字符串。大概是这样的：

 select * from 
 (
 select datepart(dw,b.Date) as Tag,b.[Customer No_],b.Date,b.[POS Holiday],b.Nonworking,
 case
  when datepart(dw,b.Date)=1 then (select '[Valid at Monday]=1')
  when datepart(dw,b.Date)=2 then (select '[Valid at Tuesday]=1')
  when datepart(dw,b.Date)=3 then (select '[Valid at Wednesday]=1')
  when datepart(dw,b.Date)=4 then (select '[Valid at Thursday]=1')
  when datepart(dw,b.Date)=5 then (select '[Valid at Friday]=1')
  when datepart(dw,b.Date)=6 then (select '[Valid at Saturday]=1')
  when datepart(dw,b.Date)=7 then (select '[Valid at Sunday]=1')
 end as  TestB 
 from [CustomerBPCal] b
 ) as a 
 left join [CustomerShopAndArrivalTime] as c on c.[Customer No_]=a.[Customer No_]  where a.TestB 

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如果是，如何更改代码以运行此类查询？

条件属于

WHERE

子句。似乎您只是想这样做：

WHERE (datepart(dw, b.Date) = 1 And [Valid at Monday] = 1)
   OR (datepart(dw, b.Date) = 2 And [Valid at Tuesday] = 1)
   OR ...

或者，如果

[在…]有效

列属于外部联接表

CustomerShopArrivalTime

，则在

ON

子句中：

ON c.[Customer No_] = a.[Customer No_]  
AND
(   (datepart(dw, b.Date) = 1 And c.[Valid at Monday] = 1)
 OR (datepart(dw, b.Date) = 2 And c.[Valid at Tuesday] = 1)
 OR ...
)

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是否要添加

，其中a.testb='somevalue'

？如果是，请随意添加和检查。例如，我想使用“where'[周一有效]=1”