Grouping by most commonly repeated values - sql

Question

I have series of data like below
PRICE AMOUNT TOTAL BUYER SELLER
2.43 250 607,5 TRADER_B TRADER_B(*)
2.43 500 1215 TRADER_D TRADER_B(*)
2.43 13000 31590 TRADER_D TRADER_B(*)
2.43 17000 41310 TRADER_C TRADER_B(*)
2.43 15000 36450 TRADER_A TRADER_B(*)
2.43 10000 24300 TRADER_E TRADER_B(*)
2.43 20000 48600 TRADER_F TRADER_B(*)
2.42 100 242 TRADER_A(*) TRADER_C
2.42 1500 3630 TRADER_A(*) TRADER_F
2.42 10000 24200 TRADER_A(*) TRADER_F
2.42 14500 35090 TRADER_A(*) TRADER_C
2.42 11000 26620 TRADER_A(*) TRADER_A
2.41 400 964 TRADER_A(*) TRADER_B
2.41 200 482 TRADER_B TRADER_C
2.41 1200 2892 TRADER_C TRADER_A
2.40 1000 2400 TRADER_B TRADER_D
2.40 15000 36000 TRADER_F TRADER_E(*)
2.40 20000 48000 TRADER_F TRADER_E(*)
2.40 7500 18000 TRADER_B TRADER_E(*)
2.40 8000 19200 TRADER_A TRADER_E(*)
2.40 2500 6000 TRADER_D TRADER_E(*)
2.40 3500 8400 TRADER_B TRADER_E(*)
My aim, to catching up most stronger buyers and sellers on a stock. That is why I need to grouping by most commonly repeated values according to the BUYER and SELLER columns (I specified the rows by *).
THE BEST BUYERS AMOUNT TOTAL
TRADER_A 37500 90746
THE BEST SELLERS AMOUNT TOTAL
TRADER_E 56500 135600
TRADER_B 75750 184072

Answer 1

If you want the aggregation based on the most common price for each buyer, it would look like:
select bp.*
from (select buyer, price, sum(amount) as amount, sum(total) as total,
row_number() over (partition by buyer order by count(*) desc) as seqnum
from t
group by buyer, price
) bp
where seqnum = 1;