Indexes are the feature intended to fit this requirement. The insertions can also be done with PROC SQL or with a DATA step (using the MODIFY statement). Whether this approach is advantageous vis a vis appending and sorting will depend on the particulars. DLing wrote: Just a thought, if the large base dataset is indexed (create via PROC datasets), then proc datasets append statement may be able to append and update the index without physically sorting the very large tables. The link Art provided describes appending to an indexed dataset.
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