SQL与3个表的内部联接？

Question

我想在视图中加入3个表格;这里是情况：

我有一个表格，其中包含申请住在这所大学校园的学生的信息。我有另一张表格，列出了每个学生的大厅首选项（其中3个）。但是，这些偏好中的每一个都只是一个ID号码，并且ID号在第三个表中有一个对应的名称（没有设计这个数据库......）。

差不多，我有INNER上表连接自己的喜好，他们的信息，结果是一样的东西......

John Doe | 923423 | Incoming Student | 005 

凡005将是HallID。所以现在我想将HallID与第三个表相匹配，此表中包含HallID和HallName。

那么好看多了，我想我的结果是这样......

John Doe | 923423 | Incoming Student | Foley Hall <---(INSTEAD OF 005) 

编辑这里是我目前有

SELECT 
    s.StudentID, s.FName, 
    s.LName, s.Gender, s.BirthDate, s.Email, 
    r.HallPref1, r.HallPref2, r.HallPref3 
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 h 
    ON r.HallPref1 = h.HallID 

Answer 1

你可以做以下的（我猜上表中的字段等等）

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 

编辑：根据您的要求为多厅

你可以这样做。你刚才多次加入你的堂表中的每个房间PREF ID：

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 

Answer 2

如果你有相同的ID 3个表我认为它会是这样的：

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

只需将*替换为您想要从表中获得的内容即可。

Answer 3

您只需要第二个内部联接，即将您现在的ID Number链接到第三个表的ID Number。此后，由Hall Name瞧:)

更换 ID Number

Answer 4

SELECT column_Name1,column_name2,...... 
    From tbl_name1,tbl_name2,tbl_name3 
    where tbl_name1.column_name = tbl_name2.column_name 
    and tbl_name2.column_name = tbl_name3.column_name 

Answer 5

这是正确的查询加入3表相同的ID **

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'; 

员工第一个表。 报告第二张表。 诞生第三个表

Answer 6

select empid,empname,managename,[Management ],cityname 
from employees inner join Managment 
on employees.manageid = Managment.ManageId  
inner join CITY on employees.Cityid=CITY.CityId 


id name managename managment cityname 
---------------------------------------- 
1 islam hamza  it  cairo 

Answer 7

SELECT table1.col,table2.col,table3.col 
FROM table1 
INNER JOIN 
(table2 INNER JOIN table3 
ON table3.id=table2.id) 
ON table1.id(f-key)=table2.id 
AND //add any additional filters HERE 

Answer 8

SELECT * 
FROM 
    PersonAddress a, 
    Person b, 
    PersonAdmin c 
WHERE a.addressid LIKE '97%' 
    AND b.lastname LIKE 'test%' 
    AND b.genderid IS NOT NULL 
    AND a.partyid = c.partyid 
    AND b.partyid = c.partyid; 

Answer 9

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 

Answer 10

此查询会为你

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