full text search - MySQL FULLTEXT not working

Question

I'm attempting to add searching support for my PHP web app using MySQL's FULLTEXT indexes.

I created a test table (using the MyISAM type, with a single text field a) and entered some sample data. Now if I'm right the following query should return both those rows:

SELECT * FROM test WHERE MATCH(a) AGAINST('databases')

However it returns none. I've done a bit of research and I'm doing everything right as far as I can tell - the table is a MyISAM table, the FULLTEXT indexes are set. I've tried running the query from the prompt and from phpMyAdmin, with no luck. Am I missing something crucial?

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UPDATE: Ok, while Cody's solution worked in my test case it doesn't seem to work on my actual table:

CREATE TABLE IF NOT EXISTS `uploads` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` text NOT NULL,
  `size` int(11) NOT NULL,
  `type` text NOT NULL,
  `alias` text NOT NULL,
  `md5sum` text NOT NULL,
  `uploaded` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 AUTO_INCREMENT=6 ;

And the data I'm using:

INSERT INTO `uploads` (`id`, `name`, `size`, `type`, `alias`, `md5sum`, `uploaded`) VALUES
(1, '04 Sickman.mp3', 5261182, 'audio/mp3', '1', 'df2eb6a360fbfa8e0c9893aadc2289de', '2009-07-14 16:08:02'),
(2, '07 Dirt.mp3', 5056435, 'audio/mp3', '2', 'edcb873a75c94b5d0368681e4bd9ca41', '2009-07-14 16:08:08'),
(3, 'header_bg2.png', 16765, 'image/png', '3', '5bc5cb5c45c7fa329dc881a8476a2af6', '2009-07-14 16:08:30'),
(4, 'page_top_right2.png', 5299, 'image/png', '4', '53ea39f826b7c7aeba11060c0d8f4e81', '2009-07-14 16:08:37'),
(5, 'todo.txt', 392, 'text/plain', '5', '7ee46db77d1b98b145c9a95444d8dc67', '2009-07-14 16:08:46');

The query I'm now running is:

SELECT * FROM `uploads` WHERE MATCH(name) AGAINST ('header' IN BOOLEAN MODE)

Which should return row 3, header_bg2.png. Instead I get another empty result set. My options for boolean searching are below:

mysql> show variables like 'ft_%';
+--------------------------+----------------+
| Variable_name            | Value          |
+--------------------------+----------------+
| ft_boolean_syntax        | + -><()~*:""&| |
| ft_max_word_len          | 84             |
| ft_min_word_len          | 4              |
| ft_query_expansion_limit | 20             |
| ft_stopword_file         | (built-in)     |
+--------------------------+----------------+
5 rows in set (0.02 sec)

"header" is within the word length restrictions and I doubt it's a stop word (I'm not sure how to get the list). Any ideas?

Answer 1

Add more data. By default MySQL will ignore any word that is in 50% or more of the rows in the table as it considers it would be a 'noise' word.

With very few rows in a table, it is common to hit this 50% limit often (ie. if you have two rows, every word is in at least 50% of the rows!).