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SQL Basics in PostgreSQL

Get to know the data
JOIN revisited
7. JOIN reviewed
LEFT JOIN
RIGHT JOIN
FULL JOIN
OUTER JOINS
NATURAL JOIN
Aliases for tables

Instruction

Good, let's get started!

Do you still remember how we joined two tables in the second part of the course? Let's review the example we gave for people and their cars:

SELECT *
FROM person
JOIN car
  ON person.id = car.owner_id;

That's right, we put the keyword JOIN between the names of two tables and then, after another keyword ON, we provided the condition.

In this particular example, we joined the rows where value of the column owner_id (table car) was identical with the value of the column id (table person). In this way, we joined cars with their owners.

Exercise

Try it yourself. Join the two tables: student and room so that each student is shown together with the room they live in. Select all columns.

Stuck? Here's a hint!

Type:

SELECT *
FROM student
JOIN room
  ON student.room_id = room.id;