MySQL can perform boolean full-text searches using the
IN BOOLEAN MODE modifier. With this modifier,
certain characters have special meaning at the beginning or end
of words in the search string. In the following query, the
- operators indicate
that a word must be present or absent, respectively, for a match
to occur. Thus, the query retrieves all the rows that contain
the word “MySQL” but that do
not contain the word
SELECT * FROM articles WHERE MATCH (title,body)
AGAINST ('+MySQL -YourSQL' IN BOOLEAN MODE);+----+-----------------------+-------------------------------------+ | id | title | body | +----+-----------------------+-------------------------------------+ | 1 | MySQL Tutorial | DBMS stands for DataBase ... | | 2 | How To Use MySQL Well | After you went through a ... | | 3 | Optimizing MySQL | In this tutorial we will show ... | | 4 | 1001 MySQL Tricks | 1. Never run mysqld as root. 2. ... | | 6 | MySQL Security | When configured properly, MySQL ... | +----+-----------------------+-------------------------------------+
In implementing this feature, MySQL uses what is sometimes referred to as implied Boolean logic, in which
+ stands for
- stands for
[no operator] implies
Boolean full-text searches have these characteristics:
They do not use the 50% threshold that applies to
MyISAM search indexes.
They do not automatically sort rows in order of decreasing relevance.
Boolean queries against a
index can work even without a
index, although a search executed in this fashion would be
InnoDB tables require a
FULLTEXT index to perform boolean
The minimum and maximum word length full-text parameters
InnoDB search indexes, and
InnoDB full-text search does not support
the use of multiple operators on a single search word, as in
full-text search will successfully process the same search
ignoring all operators except for the operator immediately
adjacent to the search word.
The boolean full-text search capability supports the following operators:
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.
- 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
By default (when neither
- is specified), the word is optional,
but the rows that contain it are rated higher. This mimics
the behavior of
AGAINST() without the
This operator works on
only. It tests whether two or more words all start within a
specified distance from each other, measured in words.
Specify the search words within a double-quoted string
immediately before the
operator, for example,
word2 word3" @8' IN BOOLEAN MODE)
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
< 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
The asterisk serves as the truncation (or wildcard)
operator. Unlike the other operators, it is
appended to the word to be affected.
Words match if they begin with the word preceding the
If a word is specified with the truncation operator, it is
not stripped from a boolean query, even if it is too short
or a stopword. Whether a word is too short is determined
InnoDB tables, or
MyISAM tables. The wildcarded word is
considered as a prefix that must be present at the start of
one or more words. If the minimum word length is 4, a search
'+ could return fewer rows than a search for
because the second query ignores the too-short search term
A phrase that is enclosed within double quote
"”) characters matches
only rows that contain the phrase literally, as it
was typed. The full-text engine splits the phrase
into words and performs a search in the
FULLTEXT index for the words. Nonword
characters need not be matched exactly: Phrase searching
requires only that matches contain exactly the same words as
the phrase and in the same order. For example,
"test phrase" matches
If the phrase contains no words that are in the index, the result is empty. The words might not be in the index because of a combination of factors: if they do not exist in the text, are stopwords, or are shorter than the minimum length of indexed words.
The following examples demonstrate some search strings that use boolean full-text operators:
Find rows that contain at least one of the two words.
Find rows that contain both words.
Find rows that contain the word “apple”, but rank rows higher if they also contain “macintosh”.
Find rows that contain the word “apple” but not “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
-macintosh', for which the presence of
“macintosh” causes the row not to be returned
'+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”.
Find rows that contain words such as “apple”, “apples”, “applesauce”, or “applet”.
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 quotation marks that enclose the search