Question

While researching Oracle Analytics, I came across this query:

select an_id, 
    a_date, 
    min(a_date) over (
        partition by an_id, trunc(a_date) 
        order by a_date
        range between (2.5/24) preceding and (2.5/24) following
    ) mn,
    max(a_date) over (
        partition by an_id, trunc(a_date) 
        order by a_date
        range between (2.5/24) preceding and (2.5/24) following
    ) mx
from a_table

I believe this finds the min and max dates for a given an_id and a_date within a 2.5 hour period.

My question is why does this comparison between a_date (a date) and 2.5/24 (a number) work and how can it be modified for ranges of days, months, or years?

Answer 1

The date type allows arithmetic where a unit of 1 is a day, so SYSDATE + 1 is tomorrow.

For example, try select to_char(sysdate + 1/24, ‘DD-MON-YY HH:MM:SS’) from dual -> 1 hour from now.