在加入 3 个表 sql sql server 时求和 2 个 case 函数

Question

我正在尝试对我刚刚在查询中创建的两个 CASE 函数（案例语句中的 2 列 PotentialOrderGain 和 PotentialFreightLoss）求和。我需要通过将这两个案例函数相加来创建一个新列作为 NetGainLoss。我知道我可以使用 cte 方法来做到这一点。但同时，我需要将 3 个表内部连接在一起。这 3 个表是 Person.Address 和 Sales.SalesOrderHeader 和 Sales.vIndividualCustomer。我不知道如何在一个大查询中实现所有这些。请在下面找到我的查询。非常感谢！

select h.SalesOrderID,
       i.StateProvinceName as ShipToState,
       h.OrderDate,
       h.SubTotal,
       h.Freight,
       case when h.SubTotal>=1500 and h.SubTotal<2000 then 2000-h.SubTotal
       when h.SubTotal<1500 then 0
       when h.SubTotal>=2000 then 0
       end as PotentialOrderGain,
       case when h.SubTotal>=1500 and h.SubTotal<2000 then 0.22-h.Freight
       when h.SubTotal<1500 then 0
       when h.SubTotal>=2000 then 0.22-h.Freight
       end as PotentialFreightLoss
from Sales.vIndividualCustomer i
inner join Person.Address a
on a.City = i.City
inner join Sales.SalesOrderHeader h
on a.AddressID = h.ShipToAddressID
where i.StateProvinceName='California'
order by h.SalesOrderID;

Answer 1

select h.SalesOrderID,
i.StateProvinceName as ShipToState,
h.OrderDate,
h.SubTotal,
h.Freight,
SUM
(case when h.SubTotal>=1500 and h.SubTotal<2000 then 2000-h.SubTotal
when h.SubTotal<1500 then 0
when h.SubTotal>=2000 then 0
end)
-
(case when h.SubTotal>=1500 and h.SubTotal<2000 then 0.22-h.Freight
when h.SubTotal<1500 then 0
when h.SubTotal>=2000 then 0.22-h.Freight
end)
as NetFreightLoss
from Sales.vIndividualCustomer i
inner join Person.Address a
on a.City = i.City
inner join Sales.SalesOrderHeader h
on a.AddressID = h.ShipToAddressID
where i.StateProvinceName='California'
group by
h.SalesOrderID,
i.StateProvinceName as ShipToState,
h.OrderDate,
h.SubTotal,
h.Freight
order by h.SalesOrderID;

Answer 2

这可能是一种缓慢/低效的方法，因为将大量数据带入第四次连接，但它应该为您提供一个起点：

select 
    h.SalesOrderID
    ,i.StateProvinceName as ShipToState
    ,h.OrderDate
    ,h.SubTotal
    ,h.Freight
    ,SumTotals.PotentialOrderGain + SumTotals.PotentialFreightLoss as NetGainLoss
    from Sales.vIndividualCustomer i
    inner join Person.Address a on a.City = i.City
    inner join Sales.SalesOrderHeader h on a.AddressID = h.ShipToAddressID
    inner join (SELECT  ShipToAddressID,      
            case when h.SubTotal>=1500 and h.SubTotal<2000 then 2000-h.SubTotal
            when h.SubTotal<1500 then 0
            when h.SubTotal>=2000 then 0
            end as PotentialOrderGain,
            case when h.SubTotal>=1500 and h.SubTotal<2000 then 0.22-h.Freight
            when h.SubTotal<1500 then 0
            when h.SubTotal>=2000 then 0.22-h.Freight
            end as PotentialFreightLoss
            FROM Sales.SalesOrderHeader h
            )SumTotals ON a.AddressID = SumTotals.ShipToAddressID
where i.StateProvinceName='California'
order by h.SalesOrderID;