title: Remove all instances of duplicates in SAS
body: <p>I am merging two SAS datasets by ID number and would like to remove all instances of duplicate IDs, i.e. if an ID number occurs twice in the merged dataset then <strong>both</strong> observations with that ID will be deleted.</p>
  
  <p>Web searches have suggested some sql methods and nodupkey, but these are not working because they are for typical duplicate cleansing where one instance is kept and then the multiples are deleted.</p>