Hey, saitcopuroglu,
I came up with two alternatives, not sure if either really solves your problem. The first, which you may have tried, was a formula column like this:
DateDMY( Day(:PeriodBegin), Month(:PeriodBegin), 1904 );
So just fix the year at 1904, which is really year 0 for JMP date-time values. JMP does *not* offer a format with just month and day, and JMP does not have a custom formatter a la Excel that would allow you to put in letters to get just what you want. So with that approach, you are going to see the 1904
Another approach I took was:
Month(:PeriodBegin) * 100 + Day(:PeriodBegin)
That gives you something that is a number but only has the month and day in it.
But now it is not a real date, so you can't use date functions on it to extract the month or day - you'd have to do your own math.
Anyway, there are some other ideas in case they might help.
Thanks,
Eric