platform_name,

COUNT(DISTINCT trader_address) AS total_unique_traders

FROM

(

SELECT

platform_name,

seller_address AS trader_address

FROM

optimism.nft.ez_nft_sales

UNION

SELECT

platform_name,

buyer_address AS trader_address

FROM

optimism.nft.ez_nft_sales

) AS unique_traders

GROUP BY

platform_name;