如何 SELECT 查询包括联结表

Question

I have three tables:

students

student_ID
Firstname
Lastname

course

course_ID
course_Name
semester

enroll

student_ID
course_ID

enroll is the junction table instead of having the many to many relationships.

I need to create a SELECT statement that will return four columns: student_ID Firstname course_ID course_Name from two tables after enrollment. Here in the enroll table, I can only see the which student_ID is enrolled in which course_ID by there primary key. But if I want to see what is the course name reference with specific course_ID enrolled by the specific student_ID, how should I write the query.

Actually I want to fetch the student_ID , Firstname , course_ID , course_name in a website to see which is students are enrolled in which course_name not only the course_name . That is why I think I will need to write a select query.

It will be helpful if anyone can help me with that.

Answer 1

This should work for mysql or sql server, you didn't say which you were using. You might want to limit it or use a where clause if you have a lot or rows.

SELECT students.studen_ID, students.Firstname, course.course_ID, course.course_Name
FROM students
JOIN enroll ON (enroll.student_ID = students.student_ID)
JOIN course ON (course.course_ID = enroll.coruse_ID)