I think you need this query:
SELECT CompanyName, SUM(COALESCE(salary, 0) + COALESCE(bonus, 0) + COALESCE(others, 0)) AS TotalRemunaration
FROM yourTable
GROUP BY CompanyName
I use COALESCE(fieldName, 0)
that will return 0 when value of fieldName is Null.
0
solved Using sum operation