$sql_max = "SELECT max(sort) as max_sort FROM $tbl_course_user WHERE user_id='".$user_id."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH." AND user_course_cat='".$user_course_category."'";
$sql_max = "SELECT max(sort) as max_sort FROM $tbl_course_user WHERE user_id='".intval($user_id)."' AND relation_type<>".COURSE_RELATION_TYPE_RRHH." AND user_course_cat='".Database::escape_string($user_course_category)."'";