LEFT JOIN Keeps the Left Side

A `LEFT JOIN` keeps every row from the left table and fills missing right-side values with `NULL`.

SELECT d.name AS department_name, e.name AS employee_name
FROM departments AS d
LEFT JOIN employees AS e
  ON d.id = e.department_id

This is useful when you want to keep all rows from one table, even if some of them do not have a match in the other table.

In this example, Support still appears even though nobody works there.