Question

What type of join is needed when you wish to return rows that do not have matching values?

Answer 1

Explanation:

1. In Oracle, the (+) specifies that the join is an outer join (instead of an inner join as this implicit join syntax usually implies).
2. Making it an outer join means that the row should be included in the results even if that particular item is null.

Answer 2

Explanation:

OUTER JOIN is the only join which shows the unmatched rows.

In SQL the FULL OUTER JOIN combines the results of both left and right outer joins and returns all (matched or unmatched) rows from the tables on both sides of the join clause. Let's combine the same two tables using a full join. Here is an example of full outer join in SQL between two tables.