note 13557 added to function.sql-regcase.php

I have created a database and linked it to a website so the site visitors can do a query of the database based on what they input. My problem is that the query is case sensitive EX: The database info is in uppercase. They do a search for an aircraft type such as 'Cessna', but no results will be returned if what they typed as input was in lowercase. How can I create a query that is case insensitive? PLEASE email me with any helpful info, it will be greatly appreciated http://www.php.net/manual/en/function.sql-regcase.php