What are the main types of table joins in SQL and their differences?

Main types of JOINs in SQL and their differences:

• INNER JOIN — returns only the records that match the join condition in both tables.
• LEFT JOIN (LEFT OUTER JOIN) — returns all records from the left table and matching records from the right. If there are no matches, NULLs are shown for the right table.
• RIGHT JOIN (RIGHT OUTER JOIN) — returns all records from the right table and matching records from the left. If there are no matches, NULLs are shown for the left table.
• FULL JOIN (FULL OUTER JOIN) — returns all records from both tables, with NULLs in place where there are no matches.
• 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;