获取最后交易日期的最后数据

Question

I have a table for transactions that need to display the last transaction data row. Here is the table:

Table Name : Product_detail_trx

Trans_date;  Prod_Code;  Outlet_code;   Qty;   Prev_bal_qty;
2020-02-26;  SKU1;       CNGI;          2;       1;
2020-02-20;  SKU1;       CNGI;         -3;       4;
2020-02-29;  SKU1;       CNGI;          5;       3;

I want to get the last trans_date with sum of qty and its prev_bal_qty .

The data must be shown like this:

Trans_date Outlet_Code Qty_Total  Prev_bal_qty
2020-02-29; CNGI;        4;          3;

I tried to

select Max trans_date, sum (qty) as total_qty, prev_bal_qty
group by prod_code, outlet_code, prev_bal_qty

But it showed not in group.

Answer 1

You can use window functions:

select trans_date, outlet_code, qty_total, prev_bal_qty
from (
    select
        p.*,
        sum(qty) over() total_qty,
        row_number() over(order by trans_date desc) rn
    from product_detail_trx p
) p
where rn = 1

The inner query ranks records by descending date and computes the total quantity. The outer query filters on the top record.