How to assign a unique number to each Year Month value?

[mwallman]

Hi,

I have a YearMonth field where the values are like:

2015-Jan

2015-Feb

2015-Mar

etc

How can create a unique number that gets assigned to each value above? E.g. 2015-Jan would get 1, 2015-Feb would get 2... etc

[sunny_talwar]

Try AutoNumber(YearMonth)

but make sure that your YearMonth field is sorted in ascending order before you use AutoNumber