Something
public php v1 · immutable $sql = "SELECT t.teacherID, CONCAT(t.firstName,' ',t.lastName) fullName FROM teachers t, teachers_booking tb, guests_booking gb WHERE t.teacherID=tb.teacherID AND t.teacherID!='". $responsibleTeacherID ."' AND tb.teacherBookingID=gb.teacherBookingID AND (gb.fromDate BETWEEN '". $arrayWeekDates[0] ."' AND '". $arrayWeekDates[6] ."') AND (gb.tilDate BETWEEN '". $arrayWeekDates[0] ."' AND '". $arrayWeekDates[6] ."') GROUP BY t.teacherID ORDER BY fullName