Question

I need some help in constructing an oracle query that will pull values for 2 days previous.

The timestamp column (number) values look like this 201106210000.
The other date like number columns have values like this:
year=2011 quarter=2 month=6 day=20

Where does it make sense to do the date arithmetic? using the timestamp or should I used these other calendar columns?

The table also has these date attributes:

 Name                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 YEAR                           NUMBER
 QUARTER                        NUMBER
 MONTH                          NUMBER
 DAY                            NUMBER
 HOUR                           NUMBER
 TIMESTAMP                      NUMBER
 CNT_N                                          NUMBER

Answer 1

First, this table is a crappy way to store dates (which hopefully you are aware of). Why not either a DATE or TIMESTAMP column?

If that is out of your control, I would recommend using a to_date() on a concatenation of the YEAR, MONTH, and DAY columns so you have an actual DATE to work with. Something like:

select *
from table
where to_date(year||'/'||month||'/'||day, 'YYYY/MM/DD') >= trunc(sysdate) - 2

Since your columns aren’t real date columns you would need a function-based index to avoid a full table scan using this method.