This web site's search function supports the following boolean search operators in the keywords field:

• +

• A leading plus sign indicates that this word must be present in each row that is returned.

• -

• A leading minus sign indicates that this word must not be present in any of the rows that are returned.

• Note: The - operator acts only to exclude rows that are otherwise matched by other search terms. Thus, a boolean-mode search that contains only terms preceded by - returns an empty result. It does not return “all rows except those containing any of the excluded terms.”

• (no operator)

• By default (when neither + nor - is specified) the word is optional, but the rows that contain it are rated higher.

• > <

• These two operators are used to change a word's contribution to the relevance value that is assigned to a row. The > operator increases the contribution and the < operator decreases it. See the example following this list.

• ( )

• Parentheses group words into subexpressions. Parenthesized groups can be nested.

• ~

• A leading tilde acts as a negation operator, causing the word's contribution to the row's relevance to be negative. This is useful for marking “noise” words. A row containing such a word is rated lower than others, but is not excluded altogether, as it would be with the - operator.

• *

• The asterisk serves as the truncation (or wildcard) operator. Unlike the other operators, it should be appended to the word to be affected. Words match if they begin with the word preceding the * operator.

• "

• A phrase that is enclosed within double quote (‘"’) characters matches only rows that contain the phrase literally, as it was typed. For example, "test phrase" does not match "test, phrase".

• If the phrase contains no words that are in the index, the result is empty. For example, if all words are either stopwords or shorter than the minimum length of indexed words, the result is empty.

The following examples demonstrate some search strings that use boolean search operators:

• 'apple banana'

• Find rows that contain at least one of the two words.

• '+apple +juice'

• Find rows that contain both words.

• '+apple macintosh'

• Find rows that contain the word “apple”, but rank rows higher if they also contain “macintosh”.

• '+apple -macintosh'

• Find rows that contain the word “apple” but not “macintosh”.

• '+apple ~macintosh'

• Find rows that contain the word “apple”, but if the row also contains the word “macintosh”, rate it lower than if row does not. This is “softer” than a search for '+apple -macintosh', for which the presence of “macintosh” causes the row not to be returned at all.

• '+apple +(>turnover <strudel)'

• Find rows that contain the words “apple” and “turnover”, or “apple” and “strudel” (in any order), but rank “apple turnover” higher than “apple strudel”.

• 'apple*'

• Find rows that contain words such as “apple”, “apples”, “applesauce”, or “applet”.

• '"some words"'

• Find rows that contain the exact phrase “some words” (for example, rows that contain “some words of wisdom” but not “some noise words”). Note that the ‘"’ characters that enclose the phrase are operator characters that delimit the phrase. They are not the quotes that enclose the search string itself.