SELECT T.user_id,
       SUM(CASE WHEN T.id > P.id THEN 1 ELSE 0 END) AS Cantidad
       FROM tabla T
       LEFT JOIN (SELECT user_id, MAX(id) AS id
                    FROM tabla
                    WHERE operador = 2
                    GROUP BY user_id
              ) P
              ON P.user_id = T.user_id
       GROUP BY T.user_id