How to check the combinations in Crystal Reports?

Question

Hi 2 all

How to combination cheking in formula fields using crystal reports

mean in other lang
if(table1.Partytype and table2.partytype="seller")
{
  console.writeLine(Table1.partype);
}

Normally we will check like this


i want to  write formula field  in crystal reports same as above


How?help me
thanks inadvance