Hiding null values in a column in SAP Crystal Reports

I am not sure where this formula is written. You have to write this formula in suppress part of Section Expert.

To open section expert, right-click Report Header → Section Expert  click x→2 or suppress

Also, note that you can write the formula in any section where data is present in your report. Try below formula

ToNumber({Choice_.Choice1}) > 0 //You have to ensure choice1 should always a numeric value else report throws exception