SELECT c.timestamp, c.wert, UNIX_TIMESTAMP( c.timestamp ) AS unix_time, a.wert
FROM (

SELECT c.timestamp AS stamp1, max( a.Zeitstempel ) AS stamp2
FROM Counter.`99999910` AS c
LEFT JOIN alt.`statusanz` AS a ON c.timestamp >= a.Zeitstempel
GROUP BY c.timestamp
) AS jdhhe
LEFT JOIN c ON c.timestamp = stamp1
LEFT JOIN a ON a.Zeitstempel = stamp2
LIMIT 0 , 30