Crosstabs Crystal Reports Null value vs zero - crystal-reports

Question

I'm creating a crosstab report showing the survey history for gopher tortoises (if you must know what that is) monitoring stations. Not all stations are monitored for a given survey and sometimes when we monitor we don't find any and thus record a 0 which is a valid result.
In the crosstab when the station isn't used I would like it to say "N/A" or some other equivalent, but when it's a zero I want it to stay as zero.
I've found so much on how to change a null to a zero, but nothing when you want to keep the zero and somehow note the null.
Below is what the crosstab should look like. You'll see that the 0 in Station4 on 1/1/2004 is "real" (meaning we didn't find any) but all of the N/A's are when we didn't use the station.
Survey Dates
| | 1/1/2000 | 1/1/2002 | 1/1/2004 | 1/1/2006 |
|----------|----------|----------|----------|----------|
| Station1 | 9 | 5 | N/A | N/A |
| Station2 | 5 | 7 | 2 | 6 |
| Station3 | N/A | N/A | 6 | 9 |
| Station4 | 10 | 9 | 0 | 11 |
This is what the Oracle table look like for the 1/1/2000 survey as an example
| SurveyID | StationID | Number |
|----------|-----------|--------|
| 1 | 1 | 9 |
| 1 | 2 | 5 |
| 1 | 4 | 6 |
So, basically how to I keep the zero's and put some text in the nulls in a CR crosstab?
Thanks!

Answer 1

Because CR doesn't differentiate between nulls and actual zeros in the crosstab, you can try replacing actual zero values with a placeholder so you can tell the difference. Note that this solution will only work if you are trying to display the values and not do any aggregate calculations.
First, create a formula that will replace the zeros with a placeholder value. In this case, I'm using -1 since that number should never appear in the database.
//{#Survey Num}
local numbervar totalSurvey;
totalSurvey:={Table.ActiveBurrows} + {Table.InactiveBurrows};
if totalSurvey=0 then -1 else totalSurvey
Use this formula to create your crosstab. Now you need to set a display string so that everything appears correctly. Right-click one of your crosstab cells → hit "Format Field" → select the "Common" tab → then create a "Display String" formula. That formula should be something like:
if currentfieldvalue=-1 then "0" else if currentfieldvalue=0 then "N/A" else totext(currentfieldvalue,0,'')
Now you're basically just printing the real values over top of the placeholders.