如何使用外键链接3个表？

Question

I have made a table named "reservations" which contains a customer id and a house id. I made tables for houses and customers as well. I have made a datagrid, which contains the reservations data, but I also want it to contain the customers surname and the house code.

My tables are (in SQL Server Express):

CREATE TABLE [dbo].[houses] 
(
    [Id]     INT IDENTITY (1, 1) NOT NULL,
    [Code]   VARCHAR(50) NULL,
    [Status] VARCHAR(50) NULL,
    PRIMARY KEY CLUSTERED ([Id] ASC)
);

CREATE TABLE [dbo].[customers] 
(
    [Id]       INT IDENTITY (1, 1) NOT NULL,
    [Forename] VARCHAR(50) NULL,
    [Surname]  VARCHAR(50) NULL,
    [Email]    VARCHAR(50) NULL,
    PRIMARY KEY CLUSTERED ([Id] ASC)
);

CREATE TABLE [dbo].[reservations] 
(
    [Id]         INT  IDENTITY (1, 1) NOT NULL,
    [HouseId]    INT  NULL,
    [CustomerId] INT  NULL,
    [StartDate]  DATE NULL,
    [EindDate]   DATE NULL,
    PRIMARY KEY CLUSTERED ([Id] ASC), 
    CONSTRAINT [FK_HouseId] 
        FOREIGN KEY ([HouseId]) REFERENCES [houses]([Id]), 
    CONSTRAINT [FK_CustomerId] 
        FOREIGN KEY ([CustomerId]) REFERENCES [customers]([Id])
);

I already created all the tables, but I don't know how to link them properly. I want to get the data and put it in a datagrid.

Answer 1

To select all data from Reservations, customers' Surname and house code, you need to run query:

Select R.*, C.Surname, H.Code 
From [dbo].[reservations] R
inner join [dbo].[customers]  C on C.Id = R.CustomerId
inner join [dbo].[houses]  H on H.Id = R.HouseId

Answer 2

Try this:

select r.*,c.surname,h.code from reservation r,customers c,houses h where 
r.customer_id=c.customer_id and r.house_id=h.house_id