select date_trunc('month', block_timestamp::date) as month,

avg(price_usd) as avg_ethereum_NFT_USD_price, median(price_usd) as med_ethereum_NFT_USD_price

from ethereum.core.ez_nft_sales

where 1=1

and block_timestamp::date >= '2020-05-01'

group by 1

),

o as (

select date_trunc('month', block_timestamp::date) as month,

avg(price_usd) as avg_optimism_NFT_USD_price, median(price_usd) as med_optimism_NFT_USD_price

from optimism.core.ez_nft_sales

group by 1

)

select e.month, e.avg_ethereum_NFT_USD_price as avg_eth,

e.med_ethereum_NFT_USD_price as med_eth,

o.avg_optimism_NFT_USD_price as avg_op,

o.med_optimism_NFT_USD_price as med_op

from e join o

using(month)