Join Operators

Joins that match columns on the basis of equality are called equijoins.

Equijoins use the following comparison operators:

Joins that use the relational operators are collectively called theta joins.

These set of join operators are used for outer joins:

Operator	Action
*=	Include in the results all the rows from the first table, not just the ones where the joined columns match.
=*	Include in the results all the rows from the second table, not just the ones where the joined columns match.