select
avg(abs(period)) as average_sec, --its per seconds
max(abs(period)) as max_sec,
min(abs(period)) as min_sec
from (
SELECT
distinct BLOCK_NUMBER,
block_timestamp,
LAG(block_timestamp) IGNORE NULLS OVER (ORDER BY BLOCK_NUMBER) as last_block_timestamp,
datediff(SECOND,block_timestamp,last_block_timestamp) as period
from polygon.core.fact_blocks
order by block_timestamp asc
)