By default,
DATA step match-merging combines all observations in all input data
sets.
To exclude unmatched observations from your output data
set, use the following in your DATA step:
-
Use the IN= data set option to
create and name a variable that indicates whether the data set contributed
data to the current observation.
-
Use the subsetting IF statement
to check the IN= values and write to the merged data set only matching
observations