Incremental.sql

-- SOURCE TABLE: visits (time timestamp) partition by date(time);
-- DEST TABLE: create table daily (day date, visits int)

begin;

create temp table new_visits as 
select date(time), count(1) 
from visits 
where time >= date_sub(@prev_date, interval 5 days);

delete from daily where day in (select day from new_visits);

insert into daily (select * from new_visits);

end;