Consider the following query using the tumbling window operator:
Give an equivalent query using normal SQL constructs, without using the tumbling window operator. You can assume that the timestamp can be converted to an integer value that represents the number of seconds elapsed since (say) midnight, January 1, 1970, using the function to seconds(timestamp). You can also assume that the usual arithmetic functions are available, along with the function floor(a) which returns the largest integer ≤ a.

select item, System.Timestamp as window_end, sum(amount) from order timestamp by datetime group by itemid, tumblingwindow(hour, 1)