with tab1 as (
select BUYER as nft_buyer_1
from flow.core.fact_nft_sales
where BLOCK_TIMESTAMP>=current_date-60
),
tab2 as (
select BUYER as nft_buyer_2
from flow.core.fact_nft_sales
where BLOCK_TIMESTAMP>=current_date-53
)
select count(distinct nft_buyer_1) first_nft_buyers,count(distinct nft_buyer_2)one_week_later_nft_buyers,
(one_week_later_nft_buyers/first_nft_buyers)*100 as nft_buyer_retention_percent
from tab1
left join tab2
on tab1.nft_buyer_1=tab2.nft_buyer_2