cheatsheets/sql-join.md

title
SQL Join

SELECT * FROM order_items LEFT OUTER JOIN orders ON order_items.order_id = orders.id

   __  __
 /   /\   \
| A |u |B  |
 \___\/__ /

• inner join = u
• left outer join = A + u
• right outer join = u + B
• full outer join = A + u + B