下在手里有个序列

C4                 STOCK_CODE TDATE
556262.3942 000001 20090108
488404.1316 000001 20090108
443931.62815 000001 20090108
264990.3 000001 20090108
556262.3942 000001 20090107
488404.1316 000001 20090107
443931.62815 000001 20090107
264990.3 000001 20090107
507544.43946 000001 20090106
463432.7996 000001 20090106
442646.93037 000001 20090106
264990.3 000001 20090106


我想生成下面这个序列，而且上面那个序列不能进行排序（其实用data能解决的），我想问SQL自动生成一个序列的函数是什么？？？
556262.3942 000001 20090108  1
488404.1316 000001 20090108  2
443931.62815 000001 20090108 3
264990.3 000001 20090108  4
556262.3942 000001 20090107 1
488404.1316 000001 20090107 2
443931.62815 000001 20090107 3
264990.3 000001 20090107 4
507544.43946 000001 20090106 1
463432.7996 000001 20090106 2
442646.93037 000001 20090106 3
264990.3 000001 20090106    4