Question

Using DB2 SQL

I would like to query for records since 2:00 yesterday. I want a dynamic expression that frees me from having to manually enter the current date prior to running the query. The created_datetime attribute is of timestamp dataype.

For example:

select record_key, other_stuff
from table
where created_datetime > "2 o'clock PM yesterday"

Is this kind of dynamic timestamp comparison even possible? Eventually, I’d like to be able to do a window of time, which gets complicated!

select count(1)
from table
where created_datetime between "2 o'clock PM yesterday" and "2 o'clock PM today"

I am familiar with current date, but I am trying to conceptualize how I would leverage that. The following gets me close, but it includes everything 24 hours prior to whenever the query is run.

select count(1)
from table
where created_datetime between (currentdate - 1 day) and (currentdate @ 2 o'clock PM)

I know this is some pretty basic territory, and I feel guilty posting this question, but my research has not turned up anything for me so far. I appreciate every ounce of time spent on my behalf.

Answer 1

Try these

select record_key, other_stuff
from table
where created_datetime > CURRENT DATE - 10 HOURS

select count(1)
from table
where created_datetime between (CURRENT DATE - 10 HOURS) and (CURRENT DATE + 14 HOURS)

select count(1)
from table
where created_datetime between (CURRENT DATE - 1 DAYS) and (CURRENT DATE + 14 HOURS)

From the IBM Dev Works Library : DB2 Basics: Fun with Dates and Times

There are heaps of samples there.

E.g.

You can also perform date and time calculations using, for lack of a
better term, English:

current date + 1 YEAR 
current date + 3 YEARS + 2 MONTHS + 15 DAYS 
current time + 5 HOURS - 3 MINUTES + 10 SECONDS