Query Basics
A query is simply a description of an information need. Unlike Boolean
systems that search for just those documents containing all the
words in your query, we will search for documents that are a
best match for the words in your query. We will also search for
documents that are about the same concepts that your query describes,
so sometimes the search will bring back articles that don't mention
any of the words in your original query.
What this means is that your query -- the description of your information need -- can be as detailed as you like. Don't worry about providing too many words; the more words, the better. Additional words in your query will help the search figure out what concepts you're really interested in. On the other hand, the search will do a pretty good job of figuring out what documents are interesting to you even if your query is vague.
For example, let's say you're searching a Web site for documents about customer support for the Widget2000 product you're using. A good starting point would be
customer support for the Widget2000
If you have a question about a particular feature of the Widget2000, for example the Blurfl upgrade package, you might choose a query like
customer support for the Blurfl upgrade package
of the Widget2000
Even if there are no documents that are actually about the Blurfl upgrade, the search will still show you documents about Widget2000 customer support.
Advanced Query Tips
Here are some suggestions for getting the best results out of
the search.
Use More Words
The easiest way to narrow your search and the first thing
you should try is to simply use more words in your query. The
greater the detail you provide, the better the search is able to find
precisely what you're looking for. Also try using the
Query
By Example option on the search results page.
Use + to Require Words
Put a plus sign (+) in front of a search word and the search
will
make sure that ALL of the documents it returns contain the word.
Example search: Travel +France.
Use - to Exclude Words
Put a >minus sign (-) in front of a search word and the search
will make sure that NONE of the documents it returns contain the word.
Example search: Jaguar -car -automobiles.
Use AND, OR, NOT, AND NOT, ( )
The search supports full Boolean operators and syntax. You c
an use the AND, OR, NOT, and AND NOT operators, and parentheses ( ) for grouping
. Example search: swimming AND (man OR woman).
Using a Plus Sign (+) to Require Words
What it does:
The search will make sure that ALL of the documents it finds include
the word(s) you specify as being required.
How to use it:
In your search text, put a plus sign (+) in front of words that
must be in documents that the search finds. Do not put a space between
the plus sign (+) and the word. For example, to find documents
about hockey, but only those with the term NHL in them you could
enter:
hockey +NHL
What's different about it:
Without the plus sign (+), the search looks for documents about any
of the words in your search text. The search will rank documents
that have all of the words higher, but will also list documents
that have only some of your search words as well as documents
that may have none of your search words, but that appear to be
conceptually related.
The downside:
You may miss related documents that don't have the words you specify
as required. For example, the search "hockey +NHL"
would not include documents that have the words National Hockey
League, but not NHL.
Using a Minus Sign (-) to Exclude Words
What it does:
The search will make sure that NONE of the documents it finds contain
any word(s) you specify to exclude.
How to do it:
In your search text, put a minus sign (-) in front of words that
must not be in documents that the search finds. Do not put any space
between the minus sign (-) and the word. For example, if you want
to find documents about zeppelin aircraft but not the rock band
Led Zeppelin, you could enter: Zeppelin -Led
What's different about it:
Without the minus sign (-), the search looks for documents that are
conceptually-related to all the search words you provide, rather
than looking for items to exclude from the results.
The downside:
It's easy to exclude too much. For example, if you were looking
for information on greyhound dogs and not the bus company, the
search "greyhound -bus" would exclude a document that
was all about greyhounds, but that had the sentence "the
greyhound trainers arrived by bus."
Boolean Operators: AND, OR, NOT and ()
What they do/How to use them:
AND - Documents found must contain all words joined by the AND
operator. Note that this is equivalent to putting a plus sign
(+) in front of the word. For example, to find documents that
have all of the words wizard, oz and movie, you could enter: wizard
AND oz AND movie
OR - Documents found must contain at least one of the words joined by OR. For example, to find documents that have either the words cat or kitten you could enter: cat OR kitten
AND NOT - Documents found cannot contain the word after the term AND NOT. Note that this is equivalent to putting a minus sign (-) in front of the word. For example, to find documents that have the word pets, but not the word dogs, you could enter: pets AND NOT dogs
( ) - Parentheses are used to group portions of Boolean queries together. For example, to find documents that have the word fruit, and either the word banana or the word apple in them, you could enter: fruit AND (banana OR apple)
What's different about it:
Allows for excluding and requiring words, and complex combinations
of words.
The downside:
It's often difficult to specify exactly what you want to include
or exclude. You can also get unexpected results if you are not
careful about your use of operators and parentheses. For example,
the search bananas OR apples AND oranges is the same as the search
bananas OR (apples AND oranges). Both queries will find documents
that contain both apples and oranges, together with documents
that contain the word bananas. However, the query (bananas OR
apples) AND oranges is not the same. It will find documents containing
the word oranges and, in the same document, either bananas or
apples. Be careful out there!