我试图在一个视图中联接3个表;情况如下:

我有一张桌子,其中包含正在申请住在这个大学校园的学生的信息。我还有另一个表格,列出了每个学生的Hall Preferences(其中的3个)。但是这些首选项只是一个ID号,并且ID号在第三张表中有一个对应的Hall Name(不是设计此数据库...)。

相当多,我在INNER JOIN上带有其首选项和信息的表,结果类似于...

 John Doe | 923423 | Incoming Student | 005


其中005HallID。所以现在我想将HallID与第三个表匹配,该表包含一个HallIDHallName

非常,我希望我的结果像...

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


这里是我目前拥有的东西:

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


#1 楼

您可以执行以下操作(我猜想在表字段等)

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


根据您对多个大厅的要求,您可以执行此操作。您只需为每个房间的偏好ID在大厅桌子上多次加入:

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


评论


这仅适用于一个首选项,但是我要如何对其进行编辑以使其适用于3个首选项? (每个首选项一列)

–鲍勃·桑德斯(Bob Sanders)
2012年4月17日在17:05

@BobSanders刚刚更新了我的答案,然后,如果您不想HallPref编号,请删除这些列

– Taryn♦
2012年4月17日在17:09



#2 楼

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


评论


这个答案缺乏合理的解释来说明OP如何实现原始目标。

– gaige
2013年4月2日在2:15

#3 楼

如果您要连接3个具有相同ID的表,我想是这样的:

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


只需将*替换为您要从表中获取的内容。

#4 楼

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


#5 楼

您只需要第二个内部联接即可将您现在拥有的ID Number链接到第三张表的ID Number。然后,用ID Number替换Hall Name并贴上:)

#6 楼

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;


#7 楼

尽管有很多回应,但是总的教训似乎是,您可以在where子句中使用多个JOINS;还有techonthenet.com(我的老板向我推荐了它,这就是我找到它的方式),如果您还有其他问题并且只想尝试解决,那么它也提供了很好的SQL教程。

SELECT table1.column1
FROM table1
WHERE table1 > 0 (or whatever you want to specify)
INNER JOIN table1 
ON table1.column1 = table2.column1


#8 楼

这是对具有相同ID的联接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';


员工第一张表。
报告第二张表。
出生第三张表

#9 楼

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


#10 楼

该查询将为您服务

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


#11 楼

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)


#12 楼

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