Joining Data with SPSS
SPSS offers several commands for joining datasets.
Full Join
The primary method for any join in SPSS is the MATCH FILES command.
match files /file=LEFT /file=RIGHT /by ID.
If the datasets are known to have no overlap, the ADD FILES command is also an option.
Left Join
match files /file=LEFT /in=keep /file=RIGHT /by ID. select if keep=1.
The STAR JOIN command is also available.
Right Join
match files /file=LEFT /file=RIGHT /in=keep /by ID. select if keep=1.
Inner Join
match files /file=LEFT /in=left /file=RIGHT /in=right /by ID. select if left=1 and right=1.