数据库脚本问题，有难度

F合同编号 F存货名称  F单价            F价格调整日期             F发货日期          F供货数量      bF单价
001 c01 200.00000          2009-01-29  2009-04-21 00:00:00.000 345.00000          .00000
001 c01 200.00000  2009-01-29  2009-06-01 00:00:00.000 343.00000  .00000
001 c01 200.00000  2009-01-29  2009-07-15 00:00:00.000 300.00000   00000
002 c02 300.00000  2009-03-04  2009-03-17 00:00:00.000 455.00000          .00000
002 c02 300.00000          2009-03-04 2009-04-01 00:00:00.000 300.00000  .00000
002 c02 300.00000          2009-03-04  2009-05-01 00:00:00.000 120.00000          .00000
002 c02 300.00000          2009-03-04  2009-05-20 00:00:00.000 2700.00000 .00000
001 c02 300.00000  2009-03-31  2009-06-01 00:00:00.000 232.00000  .00000
001 c01 250.00000          2009-04-01  2009-04-21 00:00:00.000 345.00000  .00000
001 c01 250.00000  2009-04-01  2009-06-01 00:00:00.000 343.00000   .00000
001 c01 250.00000  2009-04-01  2009-07-15 00:00:00.000 300.00000        .00000
002 c02 200.00000  2009-04-02  2009-05-01 00:00:00.000 120.00000   .00000
002 c02 200.00000  2009-04-02  2009-05-20 00:00:00.000 2700.00000 .00000
002 c01 200.00000  2009-03-09  2009-03-10 00:00:00.000 230.00000          .00000
002 c01 200.00000  2009-03-09  2009-05-01 00:00:00.000 3000.00000 .00000我现在要得到下面这样的一个结果
F合同编号 F存货名称  F单价 F价格调整日期              F发货日期                      F供货数量      bF单价
001 c02 300 2009-03-31          2009-06-01                 232          300
001 c01 250 2009-04-01          2009-04-21                 345         250
001 c01 250 2009-04-01           2009-06-01                 343          250
001 c01 250 2009-04-01                 2009-07-15                 300          250
002 c02 200 2009-04-02          2009-05-01                 120          200
002 c02 200 2009-04-02          2009-05-20                 2700 200
002 c01 200 2009-03-09          2009-03-10                 230          200
002 c01 200 2009-03-09          2009-05-01                 3000 200
002 c02 300 2009-03-04          2009-03-17                 455          300
002 c02 300 2009-03-04          2009-04-01                 300          300 注意看两个时间  F价格调整日期   F发货日期。更新，然后把上面重复的删掉就可以了