Zkuste použít CASE prohlášení v rámci UPDATE příkaz
UPDATE
[yourtablename]
SET
salary =
CASE
WHEN salary BETWEEN 10000 AND 15000 THEN salary + 5000
WHEN salary BETWEEN 15000 AND 20000 THEN salary + 7000
WHEN salary BETWEEN 20000 AND 30000 THEN salary + 8000
WHEN salary BETWEEN 40000 AND 60000 THEN salary + 10000
ELSE salary
END