select avg(price) * sum(gas_used/1e9) / (avg(price) * sum(eth_value) / 1e6) as Average_cost
from ethereum.core.fact_hourly_token_prices inner join ethereum.core.fact_transactions
on hour::date=block_timestamp::date
where
TOKEN_ADDRESS is null
and hour::date > current_date - interval '30 days'
and block_timestamp::date > current_date - interval '30 days'