SELECT c.timestamp, c.wert, count( a.wert ) , avg( a.wert )
FROM Counter.`99999910` AS c
LEFT JOIN alt.`statusanz` AS a ON a.Zeitstempel
BETWEEN c.timestamp - 0.005
AND c.timestamp + 0.005
WHERE UNIX_TIMESTAMP( c.timestamp )
BETWEEN 1295859173
AND 1295869173
GROUP BY c.timestamp
LIMIT 0 , 30