SQL PHP选择具有某些数据的每个用户

Basically, I have a database with students's schedules. Each class period has its own column. I want to return every name of every user that has a certain class in a certain period.

Here is my current code. The only problem is that the code only returns the first name it finds, and not everyone with the same class.

            if ($test_stmt=$mysqli->prepare("SELECT cps_schedules_userid FROM cps_schedules WHERE monday=?")) { //Get user's ids with same class in same period
                $test_stmt->bind_param('s',$classarray_withperiod[$i]); //Bind parameters (class name)
                $test_stmt->execute(); //Execute the prepared query
                $test_stmt->store_result(); //Store result
                if ($test_stmt->num_rows()<=1) { //0 or 1 rows were returned, meaning that only the current user has this class
                }
                else { //Other people have the class, so the query returned values
                    $entirerowdata = array(); //Create array to hold all data in returned row
                    stmt_bind_assoc($test_stmt, $entirerowdata); //Get all values in row
                    $arrayofusernames=array(); //Create array to hold names of all the users
                    $arrayofusernamesindex=0;
                    while ($test_stmt->fetch()) {
                        //Convert userid -> username
                        $arrayofusernames[$arrayofusernamesindex]=$entirerowdata['cps_members_username'];
                        $arrayofusernamesindex++;
                    }
                }
            }

This is a snapshot of my cps_schedules database. It essentially goes on to the right until it reaches "friday7" :