You can aggregate your table according to records sharing the same
ende values. Then use the aggregate function
SUM to combine the other three columns. Note that
SUM will ignore
NULL values, which seems to be the behavior you want.
SELECT t1qrid, start, ende, SUM(Result) AS Result, SUM(InclLeft) AS InclLeft, SUM(InclRight) AS InclRight FROM yourTable GROUP BY t1qrid, start, ende