By "output" do you mean that you want an actual SAS date that displays that way?
Or another character variable that can't use any of the date functions?
Or a numeric value that is not in any way a date except possibly in the readers mind?
SAS date values must have month and day of month component. And a variable can only have one format in effect at any given time. What you request for "g, output will be yyyy only, if day missing, output will be yyyy-mm" is not possible with actual SAS dates.
If you want to use any of the functions such as Intck or Intnx for returning date intervals or adjusting dates, then you will have to provide a day of month and month when missing.
The informats that read yyyymm type generally assume the day of the month to be 1.
You would have to decide what makes sense for your purpose what date of the year just the year value would mean.
