DATA step match-merges
and PROC SQL joins can produce the same results. However, there are
important differences between these two techniques. For example, a
join does not require that you sort the data first; a DATA step match-merge
requires that the data be sorted.
It is useful to compare
the use of SQL joins and DATA step match-merges in the following situations:
-
when all of the values of the selected
variable match
-
when only some of the values of
the selected variable match