создание ежемесячного отчета

Надеюсь это поможет:

SELECT drivername, 
       Sum(CASE 
             WHEN weekno = 1 THEN km 
             ELSE 0 
           END) AS wk1km, 
       Sum(CASE 
             WHEN weekno = 2 THEN km 
             ELSE 0 
           END) AS wk2km, 
       Sum(CASE 
             WHEN weekno = 3 THEN km 
             ELSE 0 
           END) AS wk3km, 
       Sum(CASE 
             WHEN weekno = 4 THEN km 
             ELSE 0 
           END) AS wk4km, 
       Sum(CASE 
             WHEN weekno = 5 THEN km 
             ELSE 0 
           END) AS wk5km, 
       Sum(km)  AS total 
FROM   (SELECT drivername, 
               weekno, 
               Sum(km) km 
        FROM   traveling 
        GROUP  BY drivername, 
                  weekno) AS t 
GROUP  BY drivername 
ORDER  BY total; 

Вот пример sqlfiddle для тестирования.

Снимок демонстрационного запуска: