月份          厂商id        得分
9 1106796439172 23.8
9 1106796473938 85.6
9 1106796481411 39.63
9 1106796503057 85.72
9 1110865497984 51.49
10 1106796439172 23.8
10 1106796473938 85.6
10 1106796481411 39.63
10 1106796503057 85.72
10 1110865497984 51.49
11 1106796439172 23.8
11 1106796473938 85.6
11 1106796481411 39.63
11 1106796503057 85.72
11 1110865497984 51.49
12 1106796439172 23.8
12 1106796473938 85.6
12 1106796481411 39.63
12 1106796503057 85.72
12 1110865497984 51.49表中数据如上。请问高手如何通过一条sql语句,统计各个月份各厂商得分的排名?