Is it possible to group multiple values in one field together? For example, in Account, they have contract type P, S, O. I need to sum the contract amounts S & O together and leave P by itself.

I have tried:

```sql
select Contract_ID, Case when contract_type in ('S', 'O')then sum(to_char(nvl(contract_amount,0), '000000.99' )) when contract_type = 'P' then sum(to_char(nvl(contract_amount,0), '000000.99' ))End as Contract_Amount

sum (Case when contract_type in ('S', 'O') then to_char(nvl(contract_hours,0), '000000.99')) when contract_type = 'P' then to_char(nvl(contract_hours,0), '000000.99')) End as Contract_Hours

from Contract group by Contract_id Contract_type

```