Get post_id from slug

get-post_id-from-slug

/**
  * Get post_id from slug
  *
  * @version 0.1
  * @updated 09.10.12
  *
  **/

function get_post_id_by_slug( $slug ) {
    global $wpdb;

    $querystr = "SELECT $wpdb->posts.ID FROM $wpdb->posts WHERE $wpdb->posts.post_name = '$slug' LIMIT 1";
    $results = $wpdb->get_results( $querystr );
    if ( isset( $results[0]->ID ) AND is_numeric( $results[0]->ID ) )
        return $results[0]->ID;
    else
        return false;

} // end function get_post_id_by_slug