import pyodbc

dbfile = 'C:/Logs/N6ML/dxkmega.mdb'

cnx = pyodbc.connect('Driver={Microsoft Access Driver (*.mdb, *.accdb)};DBQ=%s' % (dbfile))
cursor = cnx.cursor().execute("select Call,[Band] from QSOs;")

by_call = {}

for call, band in cursor.fetchall():
    by_call.setdefault(call, set())
    by_call[call].add(band)

for call, bands in by_call.items():
    if len(bands) >= 9:
        srt = sorted(bands, key=lambda x: int(x[:-1]))
        print('%s has been worked on %d bands: %s' %
              (call, len(bands), ' '.join(srt)))