Match Files is alive and well, but it requires pre-sorted data. If you
use the dialog interface to perform your merges, make sure you select
“Cases are sorted in order of key variables in both datasets”, and the
dialog will generate Match Cases syntax (make sure your data file are
sorted by the key variables).
Star Join will only include cases that are present in the first file.
Any cases in the second file that are not also present in the first file
(based on the key variable values) will not be included. This is like a
SQL outer join, and unlike Match Files, which will include all cases
from both files. But it shouldn’t just “stop” when it encounters the first unmatched case.