Queries are one of the most useful tools in a database.

They allow you to take data that has been input into the database and output information (data that has context, structure and meaning).

So far you have looked at how to create a query with a single criteria.  You can use more than one criteria in a query using AND & OR.

AND Criteria

Using AND criteria allows you to search for records where two conditions have to be met.  For example, you might need to search for everyone who lives in Leicester AND are male.  In other words, city = "Leicester" AND gender="m".

OR Criteria

Using OR criteria allows you to search for records that meet one or the other criteria.  For example, we could search for customers who live in Leicester OR Birmingham.  In other words, city = "Leicester" OR city = "Birmingham".