当包含单词“ of”时，为什么此MySQLquery返回零结果？

Question

This query is returning zero results when it includes +of in the search terms:

SELECT DISTINCT *
        FROM pin
        WHERE MATCH (
        title, 
        front, 
        back, 
        price, 
        sku, 
        datereleased, 
        edition, 
        wherefrom, 
        class, 
        categories, 
        details, 
        groups, 
        associated, 
        artist) 
        AGAINST ('+Pirates +of +the +Caribbean' IN BOOLEAN MODE)
        ORDER BY pin.id DESC

Yet when I take it out, I get 1000+ rows:

'+Pirates +the +Caribbean'

Also, when I search with a phrase instead, I get 1000+ rows:

"Pirates of the Caribbean"

Why is the +of showing zero results? Are two character search words causing a problem in some way I am unaware of? I've noticed the same issues with the word +to as well.

Answer 1

If you want the word "of" to be included in fulltext searches there are two things you must do

Set minimum word length

You will have to set the ft_min_word_len to 1, by adding this to my.cnf

[mysqld]
ft_min_word_len = 1

Include more common words

I wrote a post in the DBA StackExchange on Jan 26, 2012 about defining stopwords .

By default, there are 543 built-in words considered common.

Suggestion

To create a stopword list, just make a text file and define it in my.cnf

To define the three Enlglish articles as stopwords, go to the OS and run this:

echo "a"    > /var/lib/mysql/stopwords.txt
echo "an"  >> /var/lib/mysql/stopwords.txt
echo "the" >> /var/lib/mysql/stopwords.txt
chown mysql:mysql /var/lib/mysql/stopwords.txt

If you want all words, including a , an , and the , do this:

echo -n > /var/lib/mysql/stopwords.txt
chown mysql:mysql /var/lib/mysql/stopwords.txt

Next, add these lines to my.cnf

[mysqld]
ft_min_word_len=1
ft_stopword_file=/var/lib/mysql/stopwords.txt

Next, run service mysql restart

Finally, reindex the pin table like this:

REPAIR TABLE pin QUICK;

Give it a Try !!!

Answer 2

I found the answer to my issue. Looks like FULLTEXT index searches have a ft_min_word_len value defaulted at 4 character words. I'll need to change it and rebuild my indexes if I want to search on smaller works.

Reference: http://dev.mysql.com/doc/refman/5.5/en/fulltext-fine-tuning.html

Also (thanks Dan Bracuk):

words that are present in 50% or more of the rows are considered common and do not match.

Reference: http://dev.mysql.com/doc/refman/5.5/en/fulltext-search.html

Answer 3

I didn't know so I looked it up. Found this page . It includes this phrase:

In addition, words that are present in 50% or more of the rows are considered common and do not match.