Follett VERSION 6.00 - Manual (Page 460)

04/04 460 Search Stations
Boolean search logic
In addition to refining their keyword searches by selecting a searchable field for
each search term, your patrons can use Boolean operators (AND, OR, BUT NOT)
to define the relationship between search terms:
cats AND dogs
cats dogs
You get only titles that mention both cats and dogs.
cats OR dogs
cats dogs
You get all titles that include cats, dogs, or both.
cats BUT NOT dogs
cats dogs
You get only titles about cats that do not mention dogs.
Using a second Boolean operator to add a third keyword or phrase can either
contract or expand the search results. The search order follows the same logic as
the equation ( a + b ) + c :
( cats AND dogs )
AND fish
cats dogs
fish
You get only titles that mention cats, dogs, and fish.
( cats AND dogs )
OR fish
cats dogs
fish
You get all titles that include both cats and dogs, plus all
the titles that mention fish.
( cats AND dogs )
BUT NOT fish
cats dogs
fish
You get only the titles that include cats and dogs and
do not mention fish.
Keep in mind that OR always expands a search. If the second Boolean operator is
OR, the search could have some unexpected results. For example, imagine you're
looking for books about cats that also mention either dogs or fish. The results of a
search on (cats AND dogs) OR fish will be dominated by titles about fish.
Instead, you should search for (dogs OR fish) AND cats.