For example, in any auto mobile showroom sales will happen in the same day with different time. In their sales table they add each record with time stamp. like 2021-07-21 10:00:00 , 2021-07-21 10:30:00.
So in this case higher level people want to see this day 2021-07-21 sales. In this situation Floor will help us to see that particular day sales irrespective of time.
Floor function will round down. So in this situation they will set Floor function to round the Date as 2021-07-21 00:00:00.