List only the column names of a dataset

Here's one I've used before to get a list of columns with a little bit more information, you can add the keep option as in the previous answer. This just demonstrates how to create a connection to the metadata server, in case that is useful to anyone viewing this post.

libname fetchlib meta 
    library="libraryName" metaserver="metaDataServerAddress"
    password="yourPassword" port=1234
    repname="yourRepositoryName" user="yourUserName";

proc contents data=fetchlib.YouDataSetName
    memtype=DATA 
    out=outputDataSet 
    nodetails 
    noprint; 
run;

You're using the wrong dictionary table to get column names...

proc sql ;
  select name 
  from dictionary.columns
  where memname = 'mydata'
  ;
quit ;

Or using PROC CONTENTS

proc contents data=mydata out=meta (keep=NAME) ; 
run ; 
proc print data=meta ; run ;