它们不会自动按相关性递减顺序对行进行排序。They do not automatically sort rows in order of decreasing relevance.

InnoDB 表在执行布尔查询时，需要在 MATCH() 表达式的所有列上创建 FULLTEXT 索引。针对 MyISAM 搜索索引的布尔查询即使没有 FULLTEXT 索引也能工作，尽管以这种方式执行的搜索会相当慢。InnoDB tables require a FULLTEXT index on all columns of the MATCH() expression to perform boolean queries. Boolean queries against a MyISAM search index can work even without a FULLTEXT index, although a search executed in this fashion would be quite slow.

最小和最大单词长度全文参数适用于使用内置 FULLTEXT 解析器和 MeCab 解析器插件创建的 FULLTEXT 索引。innodb_ft_min_token_size 和 innodb_ft_max_token_size 用于 InnoDB 搜索索引。ft_min_word_len 和 ft_max_word_len 用于 MyISAM 搜索索引。The minimum and maximum word length full-text parameters apply to FULLTEXT indexes created using the built-in FULLTEXT parser and MeCab parser plugin. innodb_ft_min_token_size and innodb_ft_max_token_size are used for InnoDB search indexes. ft_min_word_len and ft_max_word_len are used for MyISAM search indexes.

最小和最大词长的全文参数不适用于使用 ngram 解析器创建的 FULLTEXT 索引。ngram 令牌大小由 ngram_token_size 选项定义。Minimum and maximum word length full-text parameters do not apply to FULLTEXT indexes created using the ngram parser. ngram token size is defined by the ngram_token_size option.

停用词列表适用，由 innodb_ft_enable_stopword、innodb_ft_server_stopword_table 和 innodb_ft_user_stopword_table 控制 InnoDB 搜索索引，ft_stopword_file 控制 MyISAM 搜索索引。The stopword list applies, controlled by innodb_ft_enable_stopword, innodb_ft_server_stopword_table, and innodb_ft_user_stopword_table for InnoDB search indexes, and ft_stopword_file for MyISAM ones.

InnoDB全文搜索不支持在单个搜索词上使用多个操作符，例如：'++apple'。在单个搜索词上使用多个操作符会返回语法错误。MyISAM 全文搜索可以成功处理相同的搜索，忽略所有操作符，只考虑紧挨搜索词的操作符。InnoDB full-text search does not support the use of multiple operators on a single search word, as in this example: '++apple'. Use of multiple operators on a single search word returns a syntax error to standard out. MyISAM full-text search successfully processes the same search, ignoring all operators except for the operator immediately adjacent to the search word.

InnoDB全文搜索仅支持前置的加号或减号。例如，InnoDB支持'+apple'，但不支持'apple+'。指定后置的加号或减号会导致InnoDB报告语法错误。InnoDB full-text search only supports leading plus or minus signs. For example, InnoDB supports '+apple' but does not support 'apple+'. Specifying a trailing plus or minus sign causes InnoDB to report a syntax error.

InnoDB 全文搜索不支持在通配符中使用前导加号（'+*'）、加号和减号的组合（'+-'）或前导加号和减号组合（'+-apple'）。这些无效查询会返回语法错误。InnoDB full-text search does not support the use of a leading plus sign with wildcard ('+*'), a plus and minus sign combination ('+-'), or leading a plus and minus sign combination ('+-apple'). These invalid queries return a syntax error.

InnoDB 全文搜索不支持在布尔全文搜索中使用 @ 符号。@ 符号保留用于 @distance 接近搜索运算符。InnoDB full-text search does not support the use of the @ symbol in boolean full-text searches. The @ symbol is reserved for use by the @distance proximity search operator.

它们不使用适用于 MyISAM 搜索索引的 50% 阈值。They do not use the 50% threshold that applies to MyISAM search indexes.

+

前置或后置的加号表示该词 必须 出现在返回的每一行中。InnoDB 仅支持前置加号。A leading or trailing plus sign indicates that this word must be present in each row that is returned. InnoDB only supports leading plus signs.

-

前置或后置的减号表示该词必须 不 出现在返回的任何行中。InnoDB 仅支持前置减号。A leading or trailing minus sign indicates that this word must not be present in any of the rows that are returned. InnoDB only supports leading minus signs.

注意：- 运算符仅用于排除那些原本可由其他搜索词匹配到的行。因此，一个布尔模式搜索如果只包含前置 - 的词，将返回空结果。它不会返回 “除包含任何被排除词的行之外的所有行。””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.”

（无操作符）(no operator)

默认情况下（当未指定+或-时），该词是可选的，但包含该词的行评分更高。这模拟了MATCH() AGAINST()在未使用IN BOOLEAN MODE修饰符时的行为。By default (when neither + nor - is specified), the word is optional, but the rows that contain it are rated higher. This mimics the behavior of MATCH() AGAINST() without the IN BOOLEAN MODE modifier.

@distance

此操作符仅适用于InnoDB表。它用于测试两个或多个词是否都在指定的距离内开始，距离以词为单位。将搜索词放在紧挨着@distance操作符之前的双引号字符串中，例如，MATCH(col1) AGAINST('"word1 word2 word3" @8' IN BOOLEAN MODE)This operator works on InnoDB tables 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 @distance operator, for example, MATCH(col1) AGAINST('"word1 word2 word3" @8' IN BOOLEAN MODE)

> <

这两个运算符用于改变一个单词对分配给行的相关性值的贡献。> 运算符增加贡献，而 < 运算符减少贡献。请参见此列表后的示例。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.

( )

括号将单词归入子表达式。括起来的组可以嵌套。Parentheses group words into subexpressions. Parenthesized groups can be nested.

~

开头的波浪符号表示否定运算符，会导致该词对该行相关性的贡献为负。这对于标记“噪声”词很有用。包含这种词的行评分比其他行低，但不会像使用-运算符那样完全排除。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.

*

星号作为截断（或通配符）运算符。与其他运算符不同，它是附加在要影响的词后面。如果词以*运算符前的词开头，则匹配成功。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 * operator.

如果一个单词使用了截断操作符，即使它太短或是停用词，它也不会从布尔查询中被删除。单词是否过短由 InnoDB 表的 innodb_ft_min_token_size 设置或 MyISAM 表的 ft_min_word_len 来确定。这些选项不适用于使用 ngram 分词器的 FULLTEXT 索引。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 from the innodb_ft_min_token_size setting for InnoDB tables, or ft_min_word_len for MyISAM tables. These options are not applicable to FULLTEXT indexes that use the ngram parser.

带有通配符的单词被视为必须出现在一个或多个单词开头的前缀。如果最小单词长度为 4，则搜索'+word +the*'可能返回的行数少于搜索'+word +the'，因为第二个查询会忽略长度过短的搜索词the。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 for '+word +the*' could return fewer rows than a search for '+word +the', because the second query ignores the too-short search term the.

"

用双引号（"）括起来的短语只匹配包含该短语的行，完全按照输入的方式。全文本引擎会将短语拆分为单词，并在 FULLTEXT 索引中对这些单词执行搜索。非单词字符不需要完全匹配：短语搜索只要求匹配项包含与短语完全相同的单词并且顺序相同。例如，"test phrase" 会匹配 "test, phrase"。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 "test, phrase".

如果短语中不包含索引中的任何单词，则结果为空。单词可能不在索引中是由于多种因素的组合：如果它们在文本中不存在，是停用词，或者长度小于索引单词的最小长度。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.

'apple banana''apple banana'

查找包含至少一个这两个单词的行。Find rows that contain at least one of the two words.

'+apple +juice''+apple +juice'

查找包含两个单词的行。Find rows that contain both words.

'+apple macintosh''+apple macintosh'

查找包含单词 “apple” 的行，但如果行中也包含 “macintosh”，则排名更高。Find rows that contain the word “apple”, but rank rows higher if they also contain “macintosh”.

'+apple -macintosh''+apple -macintosh'

查找包含单词 “apple” 但不包含 “macintosh” 的行。Find rows that contain the word “apple” but not “macintosh”.

'+apple ~macintosh''+apple ~macintosh'

查找包含单词“apple”的行，但如果该行还包含单词“macintosh”，则比行中不包含时评分更低。 这比“的搜索要”温和'+apple -macintosh'，在“macintosh”存在时，该行将完全不会返回。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)''+apple +(>turnover <strudel)'

查找包含单词“apple”和“turnover”，或“apple”和“strudel”（顺序不限）的行，但将“apple turnover”排名高于“apple 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*''apple*'

查找包含如下单词的行：“apple”、“apples”、“applesauce”或“applet”。Find rows that contain words such as “apple”, “apples”, “applesauce”, or “applet”.

'"some words"''"some words"'

查找包含精确短语 “some words” 的行（例如，包含 “some words of wisdom” 的行，但不包含 “some noise words” 的行）。请注意，括住短语的 " 字符是用于分隔短语的操作符字符。它们不是括住搜索字符串本身的引号。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 string itself.