Wusste nicht das du NULL Marken hast, dann so:
SELECT w.name, t.texte, t.date, a.name FROM operator AS o
LEFT OUTER JOIN text AS t ON o.text_ID = t.ID
LEFT OUTER JOIN waren AS w ON o.waren_ID = w.ID
LEFT OUTER JOIN autor AS a ON o.autor_ID = a.ID
ORDER BY t.date DESC