date_trunc('day',a.block_timestamp) as date,

Avg(DATEDIFF(SECOND, a.block_timestamp, b.block_timestamp)) as avg_between_block_time

FROM polygon.core.fact_blocks a

JOIN polygon.core.fact_blocks b

on a.BLOCK_NUMBER = b.BLOCK_NUMBER - 1

where a.block_timestamp >= CURRENT_DATE-30

group by date

order by date