Interleaving combines
individual sorted SAS data sets into one sorted data set. You interleave
data sets by using a SET statement and a BY statement in a DATA step.
The number of observations in the new data set is the sum of the number
of observations in the original data sets.
In this section, you
will learn how to use the BY statement, how to sort data sets to prepare
for interleaving, and how to use the SET and BY statements together
to interleave observations.