How to implement FIFO in sql

Question

I working on FIFO implementation in sql. I have Batch number concept in my application. If suppose I am selling on inventory then my application should tell me that which in

Answer 1

One query .. like this

This should be tweaked for you case as you have groups and other stuff, is only for example purposes.

;with qty as (
  select 15 as value
)
,l as (
  select 
    ROW_NUMBER () over (order by accept_date desc) rn
    ,*
  from xxx
)
,q as (
  select 
    batch_no
    ,accept_date
    ,case when value>qty then value-qty else 0 end as remainder
    ,case when value>qty then qty else value end as used
    ,rn
  from l
  cross join qty
  where rn=1
  union all
  select 
    r.batch_no
    ,r.accept_date
    ,case when q.remainder>r.qty then q.remainder-r.qty else 0 end  as remainder
    ,case when q.remainder>r.qty then r.qty else q.remainder end as used
    ,r.rn
  from q 
  join l r
  on q.rn+1 = r.rn
  where  q.remainder!=0
)
select * 
from q
where used != 0

and the fiffle for it http://sqlfiddle.com/#!6/9b063/34/0