Create a formula similar to below
If month({CLIENT.CLI_UPD_DATE}) in [9, 4, 6, 11] then 30
else if month({CLIENT.CLI_UPD_DATE}) in [1, 3, 5, 7, 8, 10, 12] then 31
else
if month({CLIENT.CLI_UPD_DATE}) = 2 and isdate("Feb 29, "&totext(year({CLIENT.CLI_UPD_DATE}),0,"")) = true then 29 else 28
Replace date field with one of yours and save
right Click on Custom function and select new.
Give it a name eg NumberOfDays and select extractor
The above formula will be available to use. select it and function will build automatically. Save and then create a new formula.
In formula type function name NumberOfDays( Newdate field)
NumberOfDays will be blue to show its a function, place formula in details and it will return number of days.
Ian