variable within regular expression

Hi, This is the first time I've written to this list. If I'm not following accepted procedure, please let me know. I have a php query form in which the user input must be converted to a regular expression before querying the db. Something like this pseudo code:

        $var = $_GET['usr-input'];
        $var = '%$var%';

SELECT * FROM table WHERE field LIKE $var. I can't find the right syntax to make this work. Does anyone know? Thanks, Robbie Staufer -- -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* Robbie Staufer NCAR/SCD 1850 Table Mesa Dr. Rm. 42 Boulder, CO. 80305 (303) 497-1836