Answered By: Lynn VanLeer
Last Updated: Nov 20, 2018     Views: 5227

Boolean operators are short words that connect your keywords to create a logical phrase that a database can understand. They allow you to create a complex search that could include multiple concepts and alternative keywords.

The most common Boolean operators are AND, OR, and NOT. See how to use each of these with examples in the table below:

   Boolean Operator 

What it Does



Finds articles that use both keywords.

adult learning


online courses


          Finds articles that use either of the  keywords.

adult learners


adult students



Excludes articles that use the keyword.


NOT masters programs     


Here is an example search set up with Boolean operators in a Library database:

Advanced search set up in an EBSCO database. Search box in row one has text:  adult learn* OR adult students. Dropdown box in row two is AND. Search box in row two has text: online courses.  Dropdown box in row three is NOT. Search box in row three has text: masters programs.


Most library databases are designed to work with the above Boolean operators. Search engines, such as Google, also use Boolean operators to create complex searches.


Tips for using Boolean operators in Library databases:

  • Include one concept per search box.

  • Use the AND operator between search boxes. Caution: Connecting too many concepts with AND will make your search very narrow or could give you no results.

  • Use the OR operator with alternative terms inside a single search box. Caution: Using OR between search boxes will look for either concept in both boxes and could make your results very large.

  • Use the NOT operator by selecting it in front of the final search box to exclude the keyword in that search box. Caution: Use only when truly needed to remove a concept from your search, because it could also remove useful results.

Learn how to use Boolean Operators in the video below: 

Video:  Boolean Operators and Truncation

Video player image: Link to video Using Boolean Operators

(2 min 23 sec), Transcript 

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