INSERT INTO
    tabelle_1(
        feld_1,
        feld_2,
        ...
        feld_n
    )
SELECT
    feld_1,
    feld_2,
    ...
    feld_n
FROM
   tabelle_2 t2
WHERE
   t2.id NOT IN(
      SELECT
         t1.id
      FROM
         tabelle_1 t1
      );
   )