现有如下
idx tdate
1 2012-03-29 07:37:00.000
1 2012-03-29 09:37:00.000
2 2012-03-29 12:01:00.000
2 2012-03-29 14:25:00.000
2 2012-03-29 17:19:00.000
2 2012-03-29 20:03:00.000
2 2012-03-29 23:29:00.000
如果想在后面加一列,形成
现有如下
idx count tdate
1 1 2012-03-29 07:37:00.000
1 2 2012-03-29 09:37:00.000
2 1 2012-03-29 12:01:00.000
2 2 2012-03-29 14:25:00.000
2 3 2012-03-29 17:19:00.000
2 4 2012-03-29 20:03:00.000
2 5 2012-03-29 23:29:00.000
给表添加一个count字段?