Código SQL:
Ver originalSELECT total, patente, dni FROM(
SELECT SUM(montodanio) total, patente FROM auto AS t1
LEFT JOIN auxacc AS t2 ON (t1.patente=t2.patente)
LEFT JOIN accidente AS t3 ON (t1.idacc=t3.idacc)
) AS total
LEFT JOIN propietario AS t4 ON (t4.patente=total.patente)
WHERE total>=(SELECT avg(montodanio) FROM accidente )
Seria algo asi :)