🔗 Join Types (With Examples)

An INNER JOIN returns only the rows that have matching values in both tables. If there is no match, the row is excluded from the result.

A LEFT JOIN returns all rows from the left table, and the matched rows from the right table. If there is no match, NULLs are returned for columns from the right table.

A RIGHT JOIN returns all rows from the right table, and the matched rows from the left table. If there is no match, NULLs are returned for columns from the left table.

A FULL OUTER JOIN returns all rows when there is a match in either the left or right table. Rows with no match in one of the tables will have NULLs for the missing side.

- Use **INNER JOIN** when you only want records with matches in both tables.
- Use **LEFT JOIN** when you need all records from the left table, even if there's no match.
- Use **RIGHT JOIN** when you need all records from the right table, even if there's no match.
- Use **FULL OUTER JOIN** when you want all records from both tables, matched where possible.

SELECT Employees.name, Departments.dept_name
FROM Employees
INNER JOIN Departments ON Employees.dept_id = Departments.id;

SELECT Employees.name, Departments.dept_name
FROM Employees
LEFT JOIN Departments ON Employees.dept_id = Departments.id;

SELECT Employees.name, Departments.dept_name
FROM Employees
RIGHT JOIN Departments ON Employees.dept_id = Departments.id;

SELECT Employees.name, Departments.dept_name
FROM Employees
FULL OUTER JOIN Departments ON Employees.dept_id = Departments.id;