Appending one dataset to another.
When joining two datasets
together use PROC APPEND rather than SET. Using the SET statement means
that all observations from both files need to be read, whereas only the
new dataset need be read. For this reason, it is more efficient to
append a small (new) file to a large (base) file. If variables exist on
the new dataset which don’t appear on the base one (or vice
versa), the FORCE option must be used.
The format is of Proc Append is ;
PROC APPEND BASE (or OUT) =base-dataset
NEW (or DATA) =dataset-to-append <FORCE>;
e.g. ;
PROC APPEND OUT=CSOUTFIT NEW=HOWOUTOF FORCE;