问题
Im a little confused with the follow query we have been using for a while, The following works
Search query for "fire"
SELECT product FROM product_descriptions WHERE MATCH(product) AGAINST('+fire*' IN BOOLEAN MODE) LIMIT 5
Returns
Fire Storage 31020 S1 E
Fire Storage 31020 S1 K
Fire Storage 31021 S1 E
Fire Storage 31021 S1 K
Fire Storage 31022 S1 E
However the following search query for "keep"
SELECT product FROM product_descriptions WHERE MATCH(product) AGAINST('+keep*' IN BOOLEAN MODE) LIMIT 5
Returns no results however we have products in table such as "Fire Door Keep Shut Sign", "Keep Clear Sign"
The only word that doesnt work i've found so far is the work "keep"
The following searches work "steel", "door" as i thought it maybe a problem with double characters
回答1:
Keep is a stop-word
Wikipedia:
In computing, stop words are words which are filtered out prior to, or after, processing of natural language data (text). [...] Some tools specifically avoid removing them to support phrase search. Any group of words can be chosen as the stop words for a given purpose. For some search machines, these are some of the most common, short function words, such as the, is, at, which, and on. In this case, stop words can cause problems when searching for phrases that include them, particularly in names such as 'The Who', 'The The', or 'Take That'. Other search engines remove some of the most common words—including lexical words, such as "want"—from a query in order to improve performance.
http://dev.mysql.com/doc/refman/5.1/en/fulltext-stopwords.html
You can find the actually used list in the storage/myisam/ft_static.c file.
This fact is stated in http://dev.mysql.com/doc/refman/5.5/en/fulltext-boolean.html
You might want to use Lucene instead.
It's list of stop-words is much smaller, plus you can remove them completely:
How to instruct StandardAnalyzer in Lucene to not to remove stop words?
Or you can add
ft_stopword_file = ""
or link an empty file "empty_stopwords.txt" to your .cnf/my.ini file, restart the mysql engine and rebuild the indices:
I addition to that, if you haven't allready, lower the min word to 3 (ft_min_word_len=3) to be able to search for 3 letter words.
Shorter words (3,2) will increase the query time dramatically, especially if the fulltext indexed column fields are large.
来源：https://stackoverflow.com/questions/24952900/mysql-search-query-keep-not-working