select
case when
LOWER(SYMBOL_in)>LOWER(SYMBOL_OUT)
then concat(SYMBOL_OUT,'/',SYMBOL_in)
else
concat(SYMBOL_in,'/',SYMBOL_OUT)
end AS pair,
count(DISTINCT tx_hash) as swaps,
sum(amount_out_usd) as usd_volume
from optimism.velodrome.ez_swaps
where block_timestamp >= '2022-12-15'
and amount_out_usd is not null
group by 1
order by 3 desc
limit 10