如何从多个选择中删除所有并集，使其成为一个查询

Question

我正在尝试在一个查询中编写此代码。 我怎样才能做到这一点？

基本上我每月需要这个，所以我不能写30次。 任何可能的实现方式请分享。 在下面的查询中，相同的代码被写入3次，但日期参数不同。

Select  
case when Cast(ILE.[Posting Date] as date) <  Cast(Getdate() as date)  then cast(ILE.Quantity as Numeric(19,6)) else 0 end AS [Opening],
case when Cast(ILE.[Posting Date] as date) <=  Cast(Getdate() as date)  then cast(ILE.Quantity as Numeric(19,6)) else 0 end AS [Closing]
from  [Item Ledger Entry] ILE
where Cast(ILE.[Posting Date] as date) <= Cast(Getdate() as date)

Union all

Select  
case when Cast(ILE.[Posting Date] as date) <  Cast(Getdate()-1 as date)  then cast(ILE.Quantity as Numeric(19,6)) else 0 end AS [Opening],
case when Cast(ILE.[Posting Date] as date) <=  Cast(Getdate()-1 as date)  then cast(ILE.Quantity as Numeric(19,6)) else 0 end AS [Closing]
from [Item Ledger Entry] ILE
where Cast(ILE.[Posting Date] as date) <= Cast(Getdate()-1 as date)

union all

Select  
case when Cast(ILE.[Posting Date] as date) <  Cast(Getdate()-2 as date)  then cast(ILE.Quantity as Numeric(19,6)) else 0 end AS [Opening],
case when Cast(ILE.[Posting Date] as date) <=  Cast(Getdate()-2 as date)  then cast(ILE.Quantity as Numeric(19,6)) else 0 end AS [Closing]
from [Item Ledger Entry] ILE
where Cast(ILE.[Posting Date] as date) <= Cast(Getdate()-2 as date)

---

通过使用上面的查询https://i.stack.imgur.com/Hc6Co.png，数据将如下图所示。

Answer 1

为什么不使用CONVERT（VARCHAR（7），ILE。[Posting Date]，120），在该月份中按此分组，如果您需要按天将varchar（7）更改为varchar（10 ）。 删除并集，然后编写一个基本的聚合查询。

注意：您也可以在按组的选择部分中使用此选项，并且要细分的字段可以为您提供正确的细分。

情况以及您的范围逻辑也必须更改。

Answer 2

尝试这个：

DECLARE @DaysPast TABLE(
    Diff SMALLINT
)
DECLARE @MaxDaysPast SMALLINT=30;

WITH DaysPast(Diff) AS   
(  
    SELECT 0
    UNION ALL  
    SELECT Diff+1
    FROM DaysPast
    WHERE Diff<=@MaxDaysPast
)
INSERT INTO @DaysPast(Diff)
    SELECT *  
    FROM DaysPast  
    WHERE Diff<=@MaxDaysPast;

Select  
    case
        when Cast(ILE.[Posting Date] as date) <  Cast(DATEADD(DAYS,-1*dp.Diff,Getdate() as date)  then cast(ILE.Quantity as Numeric(19,6))
        else 0
    end AS [Opening],
    case
        when Cast(ILE.[Posting Date] as date) <=  Cast(DATEADD(DAYS,-1*dp.Diff,Getdate() as date)  then cast(ILE.Quantity as Numeric(19,6))
        else 0
    end AS [Closing]
from  [Item Ledger Entry] ILE
inner join @DaysPast dp ON Cast(ILE.[Posting Date] as date) <= Cast(DATEADD(DAYS,-1*dp.Diff,Getdate() as date)