我有 3 张桌子:客户、预订和付款
Customer
---------------
CustomerID
FirstName
Reservation
---------------
ReservationID
CustomerID (FK_Reservation_Customer)
Payment
---------------
PaymentID
ReservationID (FK_Payment_Reservation)
现在我想选择表客户并保留付款。
我有 3 张桌子:客户、预订和付款
Customer
---------------
CustomerID
FirstName
Reservation
---------------
ReservationID
CustomerID (FK_Reservation_Customer)
Payment
---------------
PaymentID
ReservationID (FK_Payment_Reservation)
现在我想选择表客户并保留付款。
您将需要JOIN
以下表格:
select *
from customer c
inner join reservation r
on c.customerid = r.customerid
left join payment p
on r.reservationid = p.reservationid
如果您在学习 JOIN 语法方面需要帮助,那么有一个很棒的 SQL 连接可视化解释会有所帮助。