Miscellany

 SELECT cs. *FROM clients_services AS csINNER JOIN (SELECT _.service_id, (SELECT _1.idFROM clients_services AS _1WHERE _1.service_id = _.service_idORDER BY _1.id DESCLIMIT 1) AS id1, (SELECT _2.idFROM clients_services AS _2WHERE _2.service_id = _.service_idAND _2.id < id1ORDER BY _2.id DESCLIMIT 1) AS id2FROM clients_services AS _GROUP BY _.service_id) AS sub ON ( cs.id = sub.id1OR cs.id = sub.id2 )