如何将条件嵌套

Question

    下面的代码是关于合同的，看起来很长，其实非常简单，筛选的条件就是TypeOfPayment（交款时间）和LeaseDateFrom（合同起始日）。

----TypeOfPayment（交款时间）有两种方式：1.月末；    2.季度末1、4、7、10  ，作为第一种筛选条件。

----LeaseDateFrom（合同起始日）和变量@Time2做比较的值，作为筛选的第二个条件

----

    我写的代码虽然可以得到正确的结果，但我想把代码变得更简单。我尝试用if 、case 等嵌套，但没有成功。下面的代码貌似很长，其实简单，几个when后面的条件都只有微小的区别。请大家帮忙看看！

 

    ------------------------------------代码---------------------------------

declare @time2 datetime
select @time2='2012-1-31'
select a.TypeOfPayment,a.LeaseDateFrom,
(case
when a.TypeOfPayment like '%月末%' 
then 1 

when TypeOfPayment='季度末7日前预交1、4、7、10' 
and ((DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))=1) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))=4) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))=7) or (DATEPART(month,DATEADD (DD,-7,a.LeaseDateFrom))=10)) 
then  2
when TypeOfPayment='季度末7日前预交1、4、7、10' 
and ((DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>1) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>4) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>7) or (DATEPART(month,DATEADD (DD,-7,a.LeaseDateFrom))<>10))
and DATEPART (MONTH,@time2)>DATEPART (MONTH ,a.LeaseDateFrom ) 
then  3
when TypeOfPayment='季度末7日前预交1、4、7、10' 
and ((DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>1) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>4) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>7) or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>10))
and DATEPART (MONTH,@time2)<DATEPART (MONTH ,a.LeaseDateFrom) 
then  4
else null

end) as 总应收
from ContractTable a join PropertyTable b on a.City +a.Road +a.[Address] =b.City +b.Road +b.[Address] 

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C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 1

抛砖引玉，看还能否更简化！

declare @time2 datetime
select @time2='2012-1-31'
select a.TypeOfPayment,a.LeaseDateFrom,
(case
when a.TypeOfPayment like '%月末%' 
then DATEDIFF(mm, DATEADD (MONTH ,-1,a.LeaseDateFrom), @time2)/12*12*a.MonthRent +
(DATEDIFF (MM,DATEADD (MONTH ,-1,a.LeaseDateFrom),@time2)%12+1)*a.MonthRent 

when TypeOfPayment='季度末7日前预交1、4、7、10' then
 case
  when  ((DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))=1) 
or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))=4) 
or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))=7) 
or (DATEPART(month,DATEADD (DD,-7,a.LeaseDateFrom))=10)) 
then  DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)/12*a.MonthRent +
DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)%12/3*3*a.MonthRent +3*a.MonthRent 

when ((DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>1) 
or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>4)
 or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>7)
  or (DATEPART(month,DATEADD (DD,-7,a.LeaseDateFrom))<>10))
and DATEPART (MONTH,@time2)>DATEPART (MONTH ,a.LeaseDateFrom ) 
then  DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)/12*a.MonthRent  +
 DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)%12/3*3*a.MonthRent +3*MonthRent

when ((DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>1) 
or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>4) 
or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>7) 
or (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))<>10))
and DATEPART (MONTH,@time2)<DATEPART (MONTH ,a.LeaseDateFrom) 
then  DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)/12*a.MonthRent  +
DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)%12/3*3*a.MonthRent 
end
else null
end) as 总应收
from ContractTable a join PropertyTable b on a.City +a.Road +a.[Address] =b.City +b.Road +b.[Address] 

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C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！

Answer 2

另外一个帖子里面回复你了

用 in 替换了 or，效率这2个都一样，不过看上去短点点。<> 用not in替换

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family as water

Answer 3

最后优化的结果发出来共享，代码缩短了一大半！

declare @time2 datetime
select @time2='2012-1-31'
select a.TypeOfPayment,a.LeaseDateFrom,
(case
when a.TypeOfPayment like '%月末%' 
then DATEDIFF(mm, DATEADD (MONTH ,-1,a.LeaseDateFrom), @time2)/12*12*a.MonthRent +
(DATEDIFF (MM,DATEADD (MONTH ,-1,a.LeaseDateFrom),@time2)%12+1)*a.MonthRent 

when TypeOfPayment='季度末7日前预交1、4、7、10' then
 case
  when  DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom))in (1,4,7,10)

then  DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)/12*a.MonthRent +
DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)%12/3*3*a.MonthRent +3*a.MonthRent 

when DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom)) not in (1,4,7,10) 

and DATEPART (MONTH,@time2)>DATEPART (MONTH ,a.LeaseDateFrom ) 
then  DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)/12*a.MonthRent  +
 DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)%12/3*3*a.MonthRent +3*MonthRent

when (DATEPART(month, DATEADD (DD,-7,a.LeaseDateFrom)) in (1,4,7,10))
and DATEPART (MONTH,@time2)<DATEPART (MONTH ,a.LeaseDateFrom) 
then  DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)/12*a.MonthRent  +
DATEDIFF (MM,dateadd(DD ,-7, a.LeaseDateFrom),@time2)%12/3*3*a.MonthRent 
end
else null
end) as 总应收
from ContractTable a join PropertyTable b on a.City +a.Road +a.[Address] =b.City +b.Road +b.[Address] 

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C# 菜鸟中的雏鸟！提的问题也许很幼稚，但我是认真的。希望看在党国的面子上拉兄弟一把！