CSV Merge Tool — illustrative example

INPUT
Left join two CSV tables on id, with unique keys. Table A:
id,name
1,Ada
2,Sam
Table B:
id,status
1,Active
3,Inactive

RESULT
id,name,status
1,Ada,Active
2,Sam,

Reconciliation: two output rows. A key 2 has no B match. B key 3 is outside the left join and is reported separately. No duplicate keys in either input.

REVIEW
Choose whether merging means appending rows or joining by a key. Specify how duplicate keys and unmatched records should be handled.

This is a teaching example, not a live execution record.