Question

我有下面的代码可以工作，并且可以完成所需的工作。

但是，我需要通过IF语句来管理两个确切的查询。

有人能看到一种消除IF的方法吗？

IF @ReportClientTypeAbbreviation = 'IA'
BEGIN
    select  
        *
    from 
        Client CR
    Inner Join LookUp.ClientType CT on 
        CR.ClientTypeID = CT.ClientTypeID
    where
        CR.SubmitDate >=@ReportStartDate and CR.SubmitDate <=@ReportEndDate and
        CT.ReportClientTypeAbbreviation = 'IA'
END
ELSE
BEGIN
    select  
        *
    from 
        Client CR
    Left Join LookUp.ClientType CT on 
        CR.ClientTypeID = CT.ClientTypeID
    where
        CR.SubmitDate >=@ReportStartDate and CR.SubmitDate <=@ReportEndDate and
        (CT.ReportClientTypeAbbreviation = 'NonIA' or CT.ReportClientTypeAbbreviation is null)
END

Answer 1

您可以使用AND / OR逻辑组合查询，这是SQL查询的基本知识。下面显示了如何执行此操作（未经测试-但应给您足够的操作空间）：

select *
from Client CR
left join LookUp.ClientType CT on CR.ClientTypeID = CT.ClientTypeID
where CR.SubmitDate >= @ReportStartDate and CR.SubmitDate <= @ReportEndDate
and (
  (CT.ReportClientTypeAbbreviation = 'IA' and @ReportClientTypeAbbreviation = 'IA')
  or (
    @ReportClientTypeAbbreviation != 'IA' and (CT.ReportClientTypeAbbreviation = 'NonIA' or CT.ReportClientTypeAbbreviation is null)
  )
)

避免IF语句控制WHERE语句

1 个答案: