case/decode-all values

:mad: By using case statement and decode, I want to see all the options mentioned in case/decode even if it is zero.

For eg.
-------
select decode(upper(group_id), 'W','White','B','Black','O','Orange','G','Green',' P','Pink','B','Blue'), count(*)
from table_a
group by group_id
order by decode(upper(group_id), 'W','B','O','G','P','B')

In this example, I would like to see the count of all the colors even if it zero. Similarly for case also.

Output:
-------
White 567
Black 0
Orange 384
Green 894
Pink 0
Blue 83

Thanks in advance.

Sathya