how to print all obs for an ID that has a flag value > 0 in any of them

[sasgorilla]

I created a flag variable where there were duplicate observations. 

To examine these further, I want to print all observations for IDs that had a flag, not just the particular ones that were flagged. The below code obviously only prints observations with a flag value. 

proc print data=a;
	where flag>0;
run;

How can I print all observations for IDs with flags? So for the below, I would want all observations of ID 1 and 3 to be printed since they had a flag value in any of the observations. 

data a;
input id var1 flag;
datalines;
1 1 0
1 1 1
2 3 0
2 2 0
3 1 0
3 2 0
3 1 1
;
run;

Thank you!

[s_lassen · Accepted solution]

You can do it like this (data must be sorted by ID, like your sample data):

data want;
  merge a(keep=id flag where=(flag>0) in=ok) a;
  by id;
  if ok;
run;

[sasgorilla]

Got it. That worked, thanks! I was thinking there was a statement within proc print but good to know a data step was needed.