[英]MySql Join three tables
我已將三個表連接到一個表中,但列名不同但值相同。
學生桌
-------------
CV_id name
-------------
LC001 ali
LC002 ahmed
LC003 john
LC004 king
課程表
-------------
Us_id name
-------------
LC001 physic
LC002 maths
LC003 computer
LC004 chemistry
橋
-------------
sid CV_cid
-------------
ti LC001
ni LC002
df LC003
ed LC004
假設您想通過id
字段加入:
select s.name student_name, c.name course_name, b.sid from student s
join course c
on c.us_id = s.cv_id
join bridge b
on b.cv_id = s.cv_id
這是有關SQL連接的一些信息
使用JOIN
實現您的結果
SELECT ST.CV_id, ST.name, CO.name, BR.`sid`
FROM Student ST
INNER JOIN Course CO ON CO.Us_id = ST.CV_id
INNER JOIN Bridge BR ON BR.CV_cid = ST.CV_id
假設您將第一列的表作為主鍵。
SELECT t1.col, t2.col, t3.col FROM tbl1 join tbl2 ON tbl1.pk = tbl2.pk join tbl3 ON tbl2.pk = tbl3.pk
您可以使用加入
SELECT s.CV_id, s.name, c.name, b.sid
FROM Student s
INNER JOIN Course c ON c.Us_id = s.CV_id
INNER JOIN Bridge b ON b.CV_cid = s.CV_id
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