Today we’re going to look at the SQL full outer join and see how we can reconstruct it using other join clauses. By doing so well get a better understand of how it and the other joins works. If you want to learn more about theses or other joins, I would encourage you to check out my online tutorial, where you can explore and practice SQL. What is an SQL Full Outer Join? A full outer join combines the characteristics of an inner join, left join, and right join into a single operation.