mysql query .. please help me

hi.

—————————————————————–
function deleteNoMatchPosts(){
global $wpdb;
$wpdb->query(“DELETE FROM $wpdb->posts WHERE post_title NOT LIKE ‘%favourite%’ “);
$wpdb->query(“DELETE FROM $wpdb->posts WHERE post_title NOT LIKE ‘%favourite1%’ “);
$wpdb->query(“DELETE FROM $wpdb->posts WHERE post_title NOT LIKE ‘%favourite2%’ “);
}

add_action(‘save_post’, ‘deleteNoMatchPosts’);

—————————————————————–

i write that code to delete post title that not match certain string.

but before do DELETE FROM blabla..

i want to select only post_title that are created past certain date say May 1 2009.

please help. thanks