Hi there,    I'm trying to clean some data by deleting observations that were entered twice - however, these were assigned unique identifiers that I need to keep for linkage purposes.   Essentially I want to run a nodupkey and sort by all variables with the exception of the observation ID's.  Is there a way to add an exception to the by_all_ command?  Something like by_all_ except obs_id ?   e.g.,  proc sort data = original_data out = dups_removed nodupkey;      by_all_; run;   Thanks! Spec   ... View more