Топ-100
 

MATCH AGAINST

База данных: MySQL
Текст

Syntax:
MATCH (col1,col2,...) AGAINST (expr [search_modifier])

MySQL has support for full-text indexing and searching:

o A full-text index in MySQL is an index of type FULLTEXT.

o Full-text indexes can be used only with InnoDB or MyISAM tables, and
can be created only for CHAR, VARCHAR, or TEXT columns.

o MySQL provides a built-in full-text ngram parser that supports
Chinese, Japanese, and Korean (CJK), and an installable MeCab
full-text parser plugin for Japanese. Parsing differences are
outlined in
https://dev.mysql.com/doc/refman/8.0/en/fulltext-search-ngram.html,
and
https://dev.mysql.com/doc/refman/8.0/en/fulltext-search-mecab.html.

o A FULLTEXT index definition can be given in the CREATE TABLE
statement when a table is created, or added later using ALTER TABLE
or CREATE INDEX.

o For large data sets, it is much faster to load your data into a table
that has no FULLTEXT index and then create the index after that, than
to load data into a table that has an existing FULLTEXT index.

Full-text searching is performed using MATCH() ... AGAINST syntax.
MATCH() takes a comma-separated list that names the columns to be
searched. AGAINST takes a string to search for, and an optional
modifier that indicates what type of search to perform. The search
string must be a string value that is constant during query evaluation.
This rules out, for example, a table column because that can differ for
each row.

There are three types of full-text searches:

o A natural language search interprets the search string as a phrase in
natural human language (a phrase in free text). There are no special
operators, with the exception of double quote (") characters. The
stopword list applies. For more information about stopword lists, see
https://dev.mysql.com/doc/refman/8.0/en/fulltext-stopwords.html.

Full-text searches are natural language searches if the IN NATURAL
LANGUAGE MODE modifier is given or if no modifier is given. For more
information, see
https://dev.mysql.com/doc/refman/8.0/en/fulltext-natural-language.htm
l.

o A boolean search interprets the search string using the rules of a
special query language. The string contains the words to search for.
It can also contain operators that specify requirements such that a
word must be present or absent in matching rows, or that it should be
weighted higher or lower than usual. Certain common words (stopwords)
are omitted from the search index and do not match if present in the
search string. The IN BOOLEAN MODE modifier specifies a boolean
search. For more information, see
https://dev.mysql.com/doc/refman/8.0/en/fulltext-boolean.html.

o A query expansion search is a modification of a natural language
search. The search string is used to perform a natural language
search. Then words from the most relevant rows returned by the search
are added to the search string and the search is done again. The
query returns the rows from the second search. The IN NATURAL
LANGUAGE MODE WITH QUERY EXPANSION or WITH QUERY EXPANSION modifier
specifies a query expansion search. For more information, see
https://dev.mysql.com/doc/refman/8.0/en/fulltext-query-expansion.html
.

URL: https://dev.mysql.com/doc/refman/8.0/en/fulltext-search.html

Пример

mysql> SELECT id, body, MATCH (title,body) AGAINST
('Security implications of running MySQL as root'
IN NATURAL LANGUAGE MODE) AS score
FROM articles WHERE MATCH (title,body) AGAINST
('Security implications of running MySQL as root'
IN NATURAL LANGUAGE MODE);
+----+-------------------------------------+-----------------+
| id | body | score |
+----+-------------------------------------+-----------------+
| 4 | 1. Never run mysqld as root. 2. ... | 1.5219271183014 |
| 6 | When configured properly, MySQL ... | 1.3114095926285 |
+----+-------------------------------------+-----------------+
2 rows in set (0.00 sec)