LEFT JOIN keeps rows with nothing to connect to

A plain JOIN only returns rows that found a match on the other side, so a student in no club quietly disappears. LEFT JOIN keeps every row from the table named first and fills the other table's columns with NULL when there is no match. Because only the first table is protected, swapping the two tables changes the result.

SELECT s.name, c.title
FROM students s
LEFT JOIN clubs c ON c.id = s.club_id;