Use `INNER JOIN` to return rows with matching values in both tables
Use `LEFT JOIN` to return all rows from the left table and matching rows from the right table
Use `RIGHT JOIN` to return all rows from the right table and matching rows from the left table
Use `FULL OUTER JOIN` to return all rows from both tables, matching where possible
Use `CROSS JOIN` to return the Cartesian product of both tables
Use `JOIN … ON` to specify the join condition
Use `JOIN … USING(column_name)` when both tables share the same column name
Use table aliases to make queries shorter and clearer
Use matching key columns such as `id`, `customer_id`, or `order_id`
Use `SELECT` to choose columns from both tables
Example: `SELECT * FROM table1 INNER JOIN table2 ON table1.id = table2.id;`