Number of passengers in each bus I

# Write your MySQL query statement below
with temp as (
select *, lag(arrival_time,1,0) over(order by arrival_time) as 'prev_time' from buses
    )

select bus_id, count(passenger_id) as passengers_cnt from temp t 
left join passengers p 
on p.arrival_time>t.prev_time and p.arrival_time<=t.arrival_time 
group by bus_id order by bus_id