select purchaser,

min(block_timestamp)::date as min_date

from solana.core.fact_nft_sales

where marketplace = 'exchange art'

and succeeded = 1

group by 1

select min_date as day,

count (distinct purchaser) as new_buyers_count,

sum (new_buyers_count) over (order by day) as cumulative_new_buyers_count

from t

where day > current_date - 90

group by 1

order by 1