Previous() Method, Check if 1st iteration 1

[1tufgt]

I'm currently using Previous() to do a running counter since I'm hiding some rows based on a formula. What's the best way to start the counter if previous doesn't work on the 1st row since there is nothing for it to compare against? I can't used ISNULL().

 

[AndyMc]

There is a function called: OnFirstRecord

So formula would be something like:

If OnFirstRecord or {table.xyz} = previous({table.xyz}) then ...

 

[kray4660]

Also previous should return a NULL on the first record.