What types of JOIN are there?

In SQL, there are several main types of JOINs that allow you to combine rows from two or more tables based on a specific condition:

• INNER JOIN — returns only the rows where there are matches in both tables.
• LEFT JOIN (LEFT OUTER JOIN) — returns all rows from the left table and the matching rows from the right; if there are no matches, NULLs are used for the right table.
• RIGHT JOIN (RIGHT OUTER JOIN) — similar to LEFT JOIN, but returns all rows from the right table and the matching rows from the left.
• FULL JOIN (FULL OUTER JOIN) — returns all rows from both tables; where there are no matches, NULLs are used in the respective fields.
• CROSS JOIN — Cartesian product of two tables, returning all possible combinations of rows.

Example of INNER JOIN:

SELECT users.name, orders.id
FROM users
INNER JOIN orders ON users.id = orders.user_id;