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select distinct date, max(sales) over (partition by date ROWS BETWEEN 1 PRECEDING AND CURRENT ROW) field from (select date, sales, dense_rank() over(order by date) rnk from (select * from(select count(inventory_id) as sales, date_format(rental_date,'%M') as date from rental group by date_format(rental_date,'%M') order by date_format(rental_date,'%M') asc) gg union all select * from(select count(inventory_id) as sales, date_format(rental_date,'%M') as date from rental group by date_format(rental_date,'%M') order by date_format(rental_date,'%M') asc) gg union all select * from(select count(inventory_id) as sales, date_format(rental_date,'%M') as date from rental group by date_format(rental_date,'%M') order by date_format(rental_date,'%M') asc) gg) ff) tt