Created
June 15, 2020 14:58
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DROP TABLE IF EXISTS club_roster; | |
DROP TABLE IF EXISTS students; | |
DROP TABLE IF EXISTS clubs; | |
CREATE TABLE clubs ( | |
id serial PRIMARY KEY, | |
name text NOT NULL | |
); | |
CREATE TABLE students ( | |
id serial PRIMARY KEY, | |
name text NOT NULL | |
); | |
CREATE TABLE club_roster ( | |
id serial PRIMARY KEY, | |
club_id integer REFERENCES clubs (id), | |
student_id integer REFERENCES students (id) | |
); | |
INSERT INTO clubs (name) | |
VALUES ('soccer'), ('baseball'), ('tennis'); | |
INSERT INTO students (name) | |
VALUES ('Gerda'), ('Lorine'), ('Karianne'), ('Destin'), ('Emilie'), ('Jerod'), ('Kristy'), ('Rodrick'); | |
INSERT INTO club_roster (club_id, student_id) | |
VALUES (1, 2), (1, 3), (2, 4), (2, 5), (2, 6), (3, 7), (3, 1); | |
-- inner join example | |
SELECT | |
students.id AS student_id, | |
students.name AS student_name | |
FROM | |
club_roster | |
INNER JOIN students ON club_roster.student_id = students.id | |
ORDER BY | |
student_id; | |
-- outer join example | |
SELECT | |
students.id AS student_id, | |
students.name AS student_name, | |
clubs.name AS club_name | |
FROM | |
students | |
LEFT OUTER JOIN club_roster ON students.id = club_roster.student_id | |
LEFT OUTER JOIN clubs ON club_roster.club_id = clubs.id | |
ORDER BY | |
student_id; | |
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