sql query stock aging

you will need to clarify a bit (best with data samples) what exactly you are trying to achieve, and what you input parameters are ...
not 100% clear so far ...

i have a stock receipts table which contain.
stockid, date, qty, rate
abc, 01/06/2011, 10, 35.25
bcd, 15/06/2011, 15,32
xyz, 01/7/2011, 25,36
qpr, 30/08/2011, 50, 40
qxy, 08/09/2011, 100 ,42

i wish to get a query on a particular day

stockid, total_stock, age0-30, age-31-60,age-61-90,age>90
abc, 10,0,0,0,10
bcd,15,0,0,0,15
qxy,100,0,100,0,0

means how old is the stock

xyz
qpr
qxy

I would do something like the following:

select stockid, sum(qty) total_stock
  , coalesce(sum("0-30"),0) "0-30"
  , coalesce(sum("31-60"),0) "31-60"
  , coalesce(sum("61-90"),0) "61-90"
  , coalesce(sum(">90"),0) ">90"
from
(
  select stockid, qty
    , case when days between 0 and 30 then qty end "0-30"
    , case when days between 31 and 60 then qty end "31-60"
    , case when days between 61 and 90 then qty end "61-90"
    , case when days > 90 then qty end ">90"
  from
  (
    select sr.stockid, sr.qty, (to_date(:baseDate) - sr.sdate) days
    from stockreceipts sr
  )
)
group by stockid
order by stockid
;