How to get DATEDIFF in Sage report to work

Hi, 

i’m trying to retrieve date difference from issued date to current date in Sage but somehow I must have my formula wrong, need some help.

I’m hoping someone can let me know what I’m doing wrong, not sure if DATEDIFF is a valid function in Sage.

PrmChg.chgdte is the date field from Prime Change Order I’m trying to calculate the date from.

(DATEDIFF(d, Date$), prmchg.chgdte)

Thank you.