ignoring mysql fulltext stopwords in query

Question

I'm building a search for a site, which utilizes a fulltext search. The search itself works great, that's not my problem. I string together user provided keywords (MATCH... AGAINST...) with AND's so that multiple words further narrow the results. Now, I know that certain stop words aren't indexed, and that's fine with me I don't really want to use them as selection criteria. But, if a stopword is provided in the keyword set (by the user), it kills all the results (as expected) even if the word actually is in a certain text block.

My question: is there any way to check to see if a certain word is a stop word at the time of the query? My preferred solution would just be to exclude the relevant word from the search criteria (I don't care if a user can narrow results by the word 'neither', I just don't want MySQL to return an empty result set because the user provided it, even though neither does exist in the results). Or, am I just going to have to empty the stopword list? Thanks very much for any help.

edit ---- I'm sorry, but there's really no code snippets to provide for this one. The code works fine, actually exactly as expected. It's more of a logical problem I'm dealing with. But as an example, in the way of explanation:

lets say there are three records, which include the words (but are not limited to)

1: apple, orange, mango, banana 2: grape, orange, pineapple, mango 3: potato, mango, melon, keira knightly

If the search word entered by the user is mango, all results are returned correctly. If the words are orange AND mango, results 1 and 2 are returned (correctly). Now, let's say banana is a stop word (it's not... but let's assume it is), if the search is for orange, mango, AND banana, no results are returned (because banana isn't in the fulltext index).

What I'm looking for is if anyone else has encountered this problem, and has a way to work around it. Sort of an:

if 'banana' NOT STOP WORD match 'banana' against `words`. (OBVIOUSLY not real code).

Or... am I just going to have to drop the stopword list...

Solution 1

You can verify the keywords by comparing all stopwords. Here is the list of stopwords I've found out a solution to disable stopwords from fulltext. You just need to locate .cnf file and add this,

ft_stopword_file = ""

restart mysql engine and rebuild indexes;

Hope this work

Solution 2

How to disable fulltext stopwords in MySQL:

In my.ini text file (MySQL) :

ft_stopword_file = ""   or link an empty file "empty_stopwords.txt"
ft_min_word_len = 2 

// set your minimum length, but be aware that shorter words (3,2) will increase the query time dramatically, especially if the fulltext indexed column fields are large.

Save the file, restart the server.

The next step should be to repair the indexes with this query:

REPAIR TABLE tbl_name QUICK.

However, this will not work if you table is using InnoDB storage engine. You will have to change it to MyISAM :

ALTER TABLE t1 ENGINE = MyISAM;

So, once again:

1. Edit my.ini file and save
2. Restart your server (this cannot be done dynamically)
3. Change the table engine (if needed)  ALTER TABLE tbl_name ENGINE = MyISAM;
4. Perform repair                       REPAIR TABLE tbl_name QUICK.

Be aware that InnoDB and MyISAM have their speed differences. One read faster, other writes faster ( read more about that on the internet )

Solution 3

disable stopword for fulltext search in mysql using this steps

1: open my.ini file in mysql

2: place below two line after [mysqld] line in my.ini (search [mysqld] in file)

ft_min_word_len=1
ft_stopword_file=""

3: restart your server

4: repair your table using below command

 > repair table tablename;

5: now your search is working....

Solution 4

For the INNODB case, it is possible to disable stop_words when you create the index.

SET @@SESSION.innodb_ft_enable_stopword = 'OFF';

create table foo
....
fulltext (search_col)

This will cause the full text index to be created with the stopwords disabled. You can verify by using the following queries.

SET GLOBAL innodb_ft_aux_table = 'schema/foo';
select * from information_schema.innodb_ft_config;

Your results will look like this:

Notice that use_stopword is set to 0.

Search for use_stopwords on this mysql documentation page. and Checkout innodb_ft_enable_stopword here

View more solutions

Comments

[dgeare]

I was thinking this might be the route I would need to go with. I was just really hoping someone else had a more clever solution. Thanks for your input.

[Félix Adriyel Gagnon-Grenier]

It should be noted that InnoDB from MySQL 5.6 has full-text indexes

[Laurent PELE]

stop words are not in full text indexes, so even if you use boolean mode, it won't return anything