CREATE TABLE `responses` ( `respondent` smallint(5) unsigned NOT NULL default '0', `response` smallint(5) unsigned NOT NULL default '0', PRIMARY KEY (`respondent`,`response`), KEY `respondent` (`respondent`), KEY `response` (`response`) ) TYPE=MyISAM 

##</code><code>##

SELECT COUNT(*) FROM theTable A JOIN theTable B ON (A.respondent = B.respondent) WHERE A.response = ? AND B.response = ?