select statement refinement

I have 3 textboxes to which people can search.

$query_findComp = "SELECT user_id, company_name, comp_add1, comp_add2, comp_add3, comp_city, comp_postcode, comp_tel, comp_fax, comp_email, comp_web, comp_description, honors_awards, industry, listed_in_bd, logo FROM users WHERE company_name LIKE '%$_GET[company]%' OR industry = '$_GET[industry]' OR comp_city = '$_GET[location]' ";

I want to be able to remove/ not send info for the blank textboxes to the query so that the search is more relevant.

Currently it will output everything.

How would I go about making this?

Thanks