Here’s a quick code snippet to convert a date in Gregorian format to Japanese Imperial Date format. The year alone would change, whereas the date and month would remain the same.
to_char(TO_DATE( A.BIRTHDATE,'YYYY/MM/DD'),'YYYY/MM/DD','NLS_CALENDAR=''Japanese Imperial''')
You can use the same code as an Expression in your PeopleSoft PS Query and it would work wonders.
Have fun! 🙂