如果你有3个具有相同ID的表要连接，我认为它会像这样:

SELECT * FROM table1 a
JOIN table2 b ON a.ID = b.ID
JOIN table3 c ON a.ID = c.ID

只需将*替换为您想从表中获得的内容。

您可以执行以下操作(我猜是在表字段等上)

SELECT s.studentname
    , s.studentid
    , s.studentdesc
    , h.hallname
FROM students s
INNER JOIN hallprefs hp
    on s.studentid = hp.studentid
INNER JOIN halls h
    on hp.hallid = h.hallid

根据你对多个大厅的要求，你可以这样做。您只需为每个房间加入您的大厅桌子多次:

SELECT     s.StudentID
    , s.FName
    , s.LName
    , s.Gender
    , s.BirthDate
    , s.Email
    , r.HallPref1
    , h1.hallName as Pref1HallName
    , r.HallPref2 
    , h2.hallName as Pref2HallName
    , r.HallPref3
    , h3.hallName as Pref3HallName
FROM  dbo.StudentSignUp AS s 
INNER JOIN RoomSignUp.dbo.Incoming_Applications_Current AS r 
    ON s.StudentID = r.StudentID 
INNER JOIN HallData.dbo.Halls AS h1 
    ON r.HallPref1 = h1.HallID
INNER JOIN HallData.dbo.Halls AS h2
    ON r.HallPref2 = h2.HallID
INNER JOIN HallData.dbo.Halls AS h3
    ON r.HallPref3 = h3.HallID

这是对id相同的连接3表的正确查询

select a.empname,a.empsalary,b.workstatus,b.bonus,c.dateofbirth from employee a, Report b,birth c where a.empid=b.empid and a.empid=c.empid and b.empid='103';

员工第一表。 报告第二表。 出生第三表

select products.product_id, product_name, price, created_at, image_name, categories.category_id, category_name,brands.brand_id, brand_name 
FROM products INNER JOIN categories USING (category_id) INNER JOIN brands USING(brand_id)

这个查询将为您工作

Select b.id as 'id', u.id as 'freelancer_id', u.name as 
'free_lancer_name', p.user_id as 'project_owner', b.price as 
'bid_price', b.number_of_days as 'days' from User u, Project p, Bid b 
where b.user_id = u.id and b.project_id = p.id

SELECT 
A.P_NAME AS [INDIVIDUAL NAME],B.F_DETAIL AS [INDIVIDUAL FEATURE],C.PL_PLACE AS [INDIVIDUAL LOCATION]
FROM 
[dbo].[PEOPLE] A
INNER JOIN 
[dbo].[FEATURE] B ON A.P_FEATURE = B.F_ID
INNER JOIN 
[dbo].[PEOPLE_LOCATION] C ON A.P_LOCATION = C.PL_ID