What is the difference between INNER JOIN, LEFT JOIN, and FULL OUTER JOIN?

INNER JOIN returns only rows where the join condition is true for BOTH tables — unmatched rows from either table are excluded. LEFT JOIN returns ALL rows from the left table and matched rows from the right; unmatched right rows are NULL. RIGHT JOIN is the mirror of LEFT JOIN. FULL OUTER JOIN returns all rows from BOTH tables; where no match exists, the other side is NULL. Venn diagram: INNER = int