How many types of joins exists in SQL(including natural join)?

There are five types of joins in SQL:

1. Inner Join: Returns records that have matching values in both tables.

2. Left (Outer) Join: Returns all records from the left table, and the matched records from the right table.

3. Right (Outer) Join: Returns all records from the right table, and the matched records from the left table.

4. Full (Outer) Join: Returns all records when there is a match in either left or right table.

5. Natural Join: A type of inner join where the join predicate arises implicitly by comparing all columns in both tables that have the same column-names in the joined tables.