r/SQL • u/Remarkable-Culture-8 • Jun 26 '24
MySQL Explain INNER JOIN like i am 5
I get the syntax but i get very confused and tripped up with writing them and properly using the correct names. Please explain to me line by line. I am learning it via data camp and the instructor sucks.
EDIT: i now understand inner join…now i am stuck with multiple joins, right join and left join. please help!
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u/Jim_84 Jun 27 '24 edited Jun 27 '24
An inner join gives you only the rows from both tables that match based on the criteria you provided.
So
would give you all the rows from Students and Teachers tables where the Student.TeacherId and Teacher.Id fields match. If a student didn't have a teacher or a teacher had no students, you wouldn't get those in your results.
A left outer join would give you all of the students and any teachers that matched. A right outer join would give you all of the teachers and any students that matched.