InfoPath Dev

Hi,
 I have an InfoPath/Sharepoint '03 form library datasource that returns all values for
ProjNum and SubProjNum from the forms submitted there.
 I am now filtering this datasource to identify the max value of the
SubProjNum's for a specific ProjNum (in order to increment by 1 for the next
sub proj form).
 My assignment looks like this:
 NewSubProjNum = max(@SubProjNum[@ProjNum = ProjNum]) + 1

 ProjNum is a value in a field on the new form and displays fine.
 max(@ProjNum) returns the max(ProjNum) from the datasource fine.
 But filtering the datasource for the max SubProjNum where @ProjNum =
ProjNum returns NaN.
count(@SubProjNum[@ProjNum = ProjNum]) = 0, even though I can see the existing record in the form library.

 Can anyone see what I am doing wrong here?
 Any suggestions?
  Thx,
  Barry

Hi,

Is the @ProjNum child of @SubProjNum in secondary data source? Once verify that. Also after selecting @SubProjNum, click on Filter data. There select the @ProjNum in the first drop down, is equal to in the second drop down and ProjNum (main  data source) in the third drop down. Click ok until all the windows gets closed.

@ProjNum and @SubProjNum are both fields returned by the secondary datasource.

My setup is exactly as you describe it, but max(@SubProjNum[@ProjNum = ProjNum]) returns NaN.

Could there be a type problem with the fields (i.e. max of an HTML string)? 

Any help would be appreciated...

Barry