业务机构     商品类别        销售金额
1001            A               20000
1001            B               60000
1002            A               30000
1002            B               90000


我想要得到一个汇总的表，如下情况：

业务机构     商品类别        销售金额
1001            A               20000
1001            B               60000
合计                            80000
1002            A               30000
1002            B               90000
合计                            120000
总合计                          200000