get file = 'c:\whatever\file1.sav'.
execute.
sort cases by MyKeyVariable.
compute dum1=1.
execute.
save /outfile = 'c:\whatever\file1.sav'.
get file = 'c:\whatever\file.sav'.
sort cases by MyKeyVariable.
compute dum2=1.
execute.
save /outfile = 'c:\whatever\file2.sav'.
match files file = 'c:\whatever\file1.sav'
/file = 'c:\whatever\file2.sav'
/by MyKeyVariable
/map .
recode dum1 dum2 (SYSMIS=0).
execute.
compute dum=dum1+dum2.
freq / dum1 dum2 dum.
temporary.
select if( dum < 2).
print / dum dum1 dum2 MyKeyVariable lname fname .
execute.