Assigning numbers by group within a table

Question

...I've found a few solutions on the internet, all of them using MYSQL specific functions though :(
Here's my table as it stands:
Account     Box     Outletnumber
1234     12345          
1234     43244                         
1234     43543
1235     32432
1235     45454
1236     23432
1237     34535
1237     45435
1237      32432
...for each unique 'account' I need to assign a sequential number to the outlet. So I should end up with:
Account     Box     Outletnumber
1234     12345     1
1234     43244     2                    
1234     43543     3
1235     32432     1
1235     45454     2
1236     23432     1
1237     34535     1
1237     45435     2
1237      32432     3
..I'm really lost on how to achieve this, anyone got any ideas?
Many thanks in advance!
Adam

Answer 1

You can use merge. If you've 10g, you may not need WHEN NOT MATCHED.
MERGE INTO <yourtable> t1 USING
(SELECT account, box, row_number() over (partition by account order by box) rno
FROM <yourtable>) t2
ON (t1.account = t2.acount
    AND t1.box = t2.box)
WHEN MATCHED THEN
     UPDATE SET outletnumber = t2.rno
WHEN NOT MATCHED THEN
     INSERT(account) VALUES(null)