Answered By: SHSU Librarian Last Updated: Oct 01, 2015 Views: 15
A Boolean operator is a word that is used to define the relationship between terms used in constructing a search in a database. There are three common Boolean operators, AND, OR, and NOT.
This YouTube video from the Lincoln Memorial University Libraries provides a fun introduction to Boolean operators, or scroll down if you prefer to read an explanation in text:
AND tells the database to return results that include both (or all) terms connected by the AND. And example would be "government AND politics AND voters". This search will return only those items that include all three terms; government, politics, and voters.
AND is used to narrow or reduce your search results. The more terms you AND into your search, the fewer results you will get because you will be putting more restrictions on what the database is to look for.
OR will return any items that include either (or any) term you use in your search. OR is used to increase, or expand, your search results.
NOT will exclude any search results that include the term or terms entered after the NOT. This can eliminate search results that you might have wanted to see, so be careful about using NOT.