Boolean Searching on Google
Last updated March 10, 2009
by Greg R. Notess
In October 2000, Google introduced support for the Boolean OR operator. With the Google default of an AND operation between terms and its support for phrase searching using the "quote marks," it is now possible to do some Boolean operations on Google. While the NOT operator itself is not supported, the minus sign "-" before a term gives the same functionality. However, bear in mind that the more complex the Boolean statement, the less likely it is that it will be interpreted properly. Some permutations come up with strange results. The following tableis designed to show what can be done and what does work, or at least has worked at sometime in the past.
|For this operation||Try this on Google|
|x AND y||x y|
|x OR y||x OR y|
|x AND (y OR z)||x y OR z|
|(x AND y) OR (z AND q)||no known option|
|(x OR y) AND (z OR q)||x OR y z OR q|
|x AND (y OR z OR q)||x y OR z OR q|
|x AND (y OR z) AND q||x y OR z q|
|x NOT y||x -y|
|(x AND y) NOT (z OR q)||x y -z -q|
Note that the OR operator must be entered in all upper case:
x OR y. If the OR operator is entered in lower case, Google ignores it.
For those of us used to using Boolean operators, we have to adapt the usual way we would run such a search. The chart above should help, but be warned that Google does tend to change its search features. These changes are often quick and unannounced.