Can you list the main types of table joins in SQL and explain their usage?

Main types of joins in SQL:

• 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 used for the right table.
• RIGHT JOIN (RIGHT OUTER JOIN) — returns all records from the right table and matching records from the left.
• FULL JOIN (FULL OUTER JOIN) — returns all records from both tables, matching and non-matching, with NULLs where there is no match.
• CROSS JOIN — Cartesian product of two tables, returning all possible combinations of rows.

Example of using INNER JOIN:

SELECT employees.name, departments.name
FROM employees
INNER JOIN departments ON employees.department_id = departments.id;

This selects employee names and their department names, only for employees who have a corresponding department.