see if:
```
select quote(deptno),
quote(job),
comm,
case deptno
when 'A00' then (comm * 1.1)
when 'D11' then (comm * 1.2)
when 'C01' then case job
when 'ANALYST' then (comm * 1.3)
when 'MANAGER' then (comm * 1.4)
else null
end
else comm
end as newcomm
from emp
where comm is not null
and deptno <> 'E21'
;
```
And see if the results shed light ...