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SQL Server 2008 - How to Join 3 tables

开发者 https://www.devze.com 2023-03-04 18:24 出处:网络
SQL Server开发者_开发百科 2008: I have 3 tables Users, Scores, Lessons Users & Scores are linked by StudentID

SQL Server开发者_开发百科 2008:

I have 3 tables

Users, Scores, Lessons

Users & Scores are linked by StudentID

Scores & Lessons are linked by LessonID

I want to display the scores for a StudentID. Here are the columns I want to display

Users.Name, Scores.LessonID, Scores.Result, Lessons.Title

I know how to Join the 2 tables. How do I throw in the 3rd table?


Same way as one table:

SELECT Users.Name, Scores.LessonID, Scores.Result, Lessons.Title
FROM Users
INNER JOIN Scores ON Users.StudentID = Scores.StudentID
INNER JOIN Lessons On Scores.LessonID = Lessons.LessonID


 SELECT *
 FROM   T1
   INNER JOIN T2
     ON T2.C = T1.C
   INNER JOIN T3
              LEFT JOIN T4
                ON T4.C = T3.C
     ON T3.C = T2.C 


is equivalent to (T1 Inner Join T2)  Inner Join (T3 Left Join T4)
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