The Question is:
How does the sort/nodups work? How does it handle a record in file1, file2,
file3 with the same key? Which of the dups records will be kept when each
have the same key yet different data?
The Answer is :
The mechanisms and details around the particular record retained
during the SORT/NODUPLICATES operation are not documented. From
the SORT help text:
"By default, Sort/Merge retains records with equal keys. The
/NODUPLICATES qualifier eliminates all but one record with equal
keys. The retained records may not appear in the same order as
they appeared in the input file. If you want to specify which
duplicate record to keep, invoke Sort at the program level and
specify an equal-key routine."