Adding to WHERE based on an IF statement in a procedure

Question

Is this legitimate?
select CRIME_CLASSIFICATION_ID, crime_type, nvl(count(CRIME_CLASSIFICATION_ID),0) as CRIMECNT
From vaps.vw_offenses
    where location_id in (vaLoc)
    If fromdate is not null Then
        AND offense_date >= to_date(fromdate, 'mm/dd/yyyy')  AND offense_date <= to_date(todate,'mm/dd/yyyy')
    End If;
group by crime_classification_id, crime_type
If it's not legitimate, how do I get the added clause into my query based on the value of fromdate?
Thanks
Chris

Answer 1

Hi, Chris,
Perhaps you want soemthing like this:
WHERE   location_id in (vaLoc)
AND     (    fromdate     IS NULL
        OR   offense_date BETWEEN TO_DATE (fromdate, 'mm/dd/yyyy')
                          AND     TO_DATE (todate,   'mm/dd/yyyy')
By the way, storing date information in string columns or variables is a really bad idea.  Use DATE columns and variables for date information; it will be simpler, more robust and more efficient; you won't need to use TO_DATE in queries like this.
I hope this answers your question.
If not, post  a little sample data (CREATE TABLE and INSERT statements, relevant columns only), and also post the results you want from that data.
Point out where the condition above is giving the wrong results, and explain, using specific examples, how you get the correct results from the given data in those places.  If you changed the condition at all, post your code.
Always say which version of Oracle you're using (e.g., 11.2.0.2.0).
See the forum FAQ: https://forums.oracle.com/message/9362002