Question

In Teradata, I need a query to first identify all members in the MEM TABLE that currently have a negative balance, let’s call that CUR_BAL. Then, for all of those members only, sum all transactions from the TRAN TABLE in order by date until the sum of those transactions is equal to the CUR_BAL.

Editing to add a third ADJ table that contains MEM_NBR, ADJ_DT and ADJ_AMT that need to be included in the running total in order to capture all of the records.

I would like the outcome to include the MEM.MEM_NBR, MEM.CUR_BAL, TRAN.TRAN_DATE OR ADJ.ADJ_DT (date associated with the transaction that resulted in the running total to equal CUR_BAL), MEM.LST_UPD_DT. I don’t need to know if the balance is negative as a result of a transaction or adjustment, just the date that it went negative.

Thank you!

Answer 1

select
    mem_nbr,
    cur_bal,
    tran_date,
    tran_type
from (
    select
        a.mem_nbr,
        a.cur_bal,
        b.tran_date,
        b.tran_type,
        a.lst_upd_dt,
        sum(b.tran_amt) over (partition by b.mem_nbr order by b.tran_date rows between unbounded preceding and current row) as cumulative_bal
    from mem a
    inner join (
        select
            mem_nbr,
            tran_date,
            tran_amt,
            'Tran' as tran_type
        from tran
        union all
        select
            mem_nbr,
            adj_date,
            adj_amt,
            'Adj' as tran_type
        from adj
    ) b
    on a.mem_nbr = b.mem_nbr
    where a.cur_bal < 0
    qualify cumulative_bal < 0
) z
qualify rank() over (partition by mem_nbr order by tran_date) = 1

The subquery picks up all instances where the cumulative balance is negative, then the outer query picks up the earliest instance of it. If you want the latest, add desc after tran_date in the final qualify line.