A join is typically used to combine results of two tables. A Join in SQL can be:-

Inner joins

Outer Joins

Left outer joins

Right outer joins

Full outer joins

Inner join

An inner join looks for matching records taken from one table from another.

A left outer join limits results to the table in left of JOIN.

A right outer join limits results to the table in right of JOIN.

Full outer joins are the combination of left and right outer joins