What are the different types of joins in SQL?

SQL supports several join types:

1. Inner Join – returns rows with matching keys in both tables.
2. Left (Outer) Join – returns all rows from the left table and matching rows from the right; unmatched right values are NULL.
3. Right (Outer) Join – returns all rows from the right table and matching rows from the left; unmatched left values are NULL.
4. Full (Outer) Join – returns all rows from both tables, filling missing side values with NULL.
5. Cross Join – returns the Cartesian product of two tables, combining every row of the first with every row of the second.
6. Self Join – a table joined to itself, useful for hierarchical or recursive queries.
7. Natural Join – automatically joins on columns with the same name in both tables.
8. Theta Join – a join using a condition other than equality (e.g., <, >).

These joins allow flexible data retrieval patterns depending on the relationship between tables.