SQL：如何組通過自定義年份

Question

對於純樸的緣故，我會做出一個類似的例子，我有什麼：

假設一個數據庫有訂單的表的訂購日期字段和公司字段。然後有一張公司表，每個記錄都有一個YearEndingDate（表示年結束於每年的這一天，例如6/6）。

我需要合計每年的所有訂單。

我認爲它必須是這樣的，但我不能完全弄清楚：

SELECT SUM(orderValue), 
CASE WHEN orderDate <= YearEndingDate THEN DatePart(year, orderDate) 
CASE WHEN orderDate > YearEndingDate THEN DatePart(year, orderDate) + 1 
END as Year 
FROM Orders 
INNER JOIN Company ON Company.companyID = Order.companyID 
GROUP By Company, Year 

任何想法？

Answer 1

不知道你正在使用什麼RDMS，但這應該做的伎倆。 datepart和dateadd是tsql特有的，但我假設你可以在任何你使用的平臺上訪問類似的函數。在哪裏決定使用哪一年的價值。

答：

select c.companyid 
     ,yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,1,o.orderdate))) as yearending 
     ,sum(ordervalue) as numberoforders 
    from @orders o 
     join @companies c 
     on o.companyid = c.companyid 
where orderdate between case when (cast(yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) as datetime) >= o.orderdate) 
         then yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,-1,o.orderdate))) 
         else yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) 
          end 
        and 
         case when (cast(yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) as datetime) >= o.orderdate) 
         then yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) 
         else yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,1,o.orderdate))) 
          end 
group by c.companyid, o.orderdate, yearendingdate 

代碼找出問題：

declare @orders table (OrderDate datetime 
         ,CompanyID varchar(20) 
         ,OrderValue int) 

insert into @orders 
values (getdate(),'MS',2) 

insert into @orders 
values (DateAdd(year, -1, getdate()),'MS',3) 

insert into @orders 
values (DateAdd(year, -1, getdate()),'MS',1) 

insert into @orders 
values (DateAdd(year, 1, getdate()),'MS',4) 

insert into @orders 
values (DateAdd(year, 1, getdate()),'Blizzard',2) 

insert into @orders 
values (getdate(),'MS',11) 

declare @companies table (CompanyID varchar(20) 
         ,YearEndingDate varchar(20)) 

insert into @companies 
values ('MS', '05/6') 

insert into @companies 
values ('Blizzard', '07/01') 

select c.companyid 
     ,o.orderdate 
     ,yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) as sameyear 
     ,yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,1,o.orderdate))) as plusyear 
     ,yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,-1,o.orderdate))) as minusyear 
    from @orders o 
     join @companies c 
     on o.companyid = c.companyid 

select c.companyid 
     ,yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,1,o.orderdate))) as yearending 
     ,sum(ordervalue) as numberoforders 
    from @orders o 
     join @companies c 
     on o.companyid = c.companyid 
where orderdate between case when (cast(yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) as datetime) >= o.orderdate) 
         then yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,-1,o.orderdate))) 
         else yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) 
          end 
        and 
         case when (cast(yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) as datetime) >= o.orderdate) 
         then yearendingdate + '/' + convert(varchar, datepart(yy, o.orderdate)) 
         else yearendingdate + '/' + convert(varchar, datepart(yy, dateadd(yy,1,o.orderdate))) 
          end 
group by c.companyid, o.orderdate, yearendingdate