Oracle Sysdate > NULL - sql

Question

I am looking into a scenario some similar to future dated stuff.
I have a table something similar to this
ProductID ProductStatus EffectiveFromDate EffectiveToDate CancelledIndicator
----------- ------------- ----------------- --------------- ------------------
345 A 7/7/2016 (null) 1
345 S 7/7/2016 11/7/2016 (null)
345 A 12/7/2016 (null) (null)
I need to fetch the current dated product
if I find a cancelled indicator it means it is no more active
if their are two rows one with future dated status.
Based on the table above I get a latest record if I check for the efd < sysdate and etd is null. but to get the current active status which is the case which i need to implement.
I need to check if the sysdate is b/w the efd and etd of the older record if not I need to take the latest record which will be the current status.
I have query which does that
but the thing is what happens when I check
sysdate between efd and etd where etd can be null most of the time.

Answer 1

Some samples of how you can handle it:
setup:
SQL> create table testNull (id, startDate, endDate) as
2 (
3 select 1, null, sysdate + 1 from dual union all
4 select 2, sysdate -1, sysdate + 1 from dual union all
5 select 3, sysdate -1, null from dual union all
6 select 4, sysdate -3, sysdate - 1 from dual
7 );
Table created.
without handling NULL:
SQL> select *
2 from testNull
3 where sysdate between startDate and endDate ;
ID STARTDATE ENDDATE
---------- --------- ---------
2 11-LUG-16 13-LUG-16
with COALESCE:
SQL> select *
2 from testNull
3 where sysdate between startDate and coalesce(endDate, sysdate);
ID STARTDATE ENDDATE
---------- --------- ---------
2 11-LUG-16 13-LUG-16
3 11-LUG-16
with some boolean logic:
SQL> select *
2 from testNull
3 where sysdate >= startDate
4 and ( endDate is null or sysdate <= endDate);
ID STARTDATE ENDDATE
---------- --------- ---------
2 11-LUG-16 13-LUG-16
3 11-LUG-16