Outer Joins
This YouTube video was created by Steve Griffith.
The LEFT JOIN
and the RIGHT JOIN
are often referred to as "Outer Joins" because they will return records outside of the matched records from the other table.
The LEFT JOIN
will return all the records from the left table (table 1), and the matched records from the right table (table 2).
# Using LEFT JOIN to combine table b and c
SELECT b.name as bname, c.name AS cname, c.id, b.best_friend
FROM b LEFT JOIN c
ON c.id = b.best_friend;
The RIGHT JOIN
will return all the records from the right table (table 2), and the matched records from the left table (table 1).
# Using RIGHT JOIN to combine table b and c
SELECT b.name as bname, c.name AS cname, c.id, b.best_friend
FROM b RIGHT JOIN c
ON c.id = b.best_friend;