使用跨多個表的多個字段來連接表

Question

我想根據多個字段連接表，其中一個來自直接表，另一個來自鄰接表。

我想加入的「裝備」，以「合同細節」上ContractDetailID只有當設備客戶id =合同客戶ID。

Answer 1

declare @contract as table(
    contractid int, 
    customerid int 
) 

declare @contractDetail as table(
    contractDetailId int, 
    ContractID int 
) 

declare @equipment as table(
    equipmentId int, 
    contractDetailId int, 
    CustomerId int 
) 

insert into @contract values(5,3) 
insert into @contractDetail values(10,5) 
insert into @equipment values(1,10,3) 

select e.* 
from 
    @contract c inner join 
    @contractDetail cd on (c.contractId = cd.contractID) inner join 
    @equipment e on (c.customerId = e.CustomerId and e.contractDetailId = cd.contractDetailId)