Oracle SQL按时间间隔分组

Question

I have a table with the following columns:

order_number
customer_number
creation_date
estimated_ship_date

I need to select the max estimated_ship_date for any records with the same customer_number and the creation_date is within 15 minutes of each other. It could be any number of records, 1-50 max I would say.

So basically group by customer_number and creation_date within 15 minutes of each other. It is the creation_date within 15 minutes of each other that I am stuck on.

Answer 1

If you will only ever have to consider rows as a group if they all fall within a single 15 minute span then you could use a windowing clause :

select order_number, customer_number, creation_date, estimated_ship_date,
  max(estimated_ship_date) over (partition by customer_number order by creation_date
    range between 15/1440 preceding and 15/1440 following) as estimated_ship_date
from cust_orders;

That gets each row of your table back with an additional column that shows the maximum ship date for any row fifteen minutes* either side of the current one.

It might not do quite what you want if you have a series of orders where each is within 15 minutes of the previous one, but they are not all within 15 minutes of all of the others - as in the example in my earlier comment. It sounds like you maybe don't expect that situation or wouldn't want to group them all together anyway, but you'd need to look at how the grouping worked if it did happen and maybe adjust it slightly.

_{* Oracle date arithmetic is based on 1 representing a full days, so 15 minutes is (15*60)/(24*60*60) seconds; or 900/86400; or 15/(24*60); or 15/1440; or 1/96; etc. Which representation you use is a matter of taste and maintainability. You can also use intervals if you prefer.}