code level date
1 a 2007-05-01
2 b 2007-05-01
3 a 2007-05-01
4 c 2007-05-01
5 e 2007-05-01
6 f 2007-05-01
7 a 2007-05-01
8 f 2007-05-02
9 a 2007-05-02
10 c 2007-05-02
11 d 2007-05-02
12 g 2007-05-02
13 a 2007-05-02
14 e 2007-05-02
我想做的是
以ID为顺序,把每天的记录的level字段的值前移到上一条,当天最后一条不处理,当天的第一条的LEVEL值不要了
结果这样的
code level date
1 b 2007-05-01
2 a 2007-05-01
3 c 2007-05-01
4 e 2007-05-01
5 f 2007-05-01
6 a 2007-05-01
7 a 2007-05-01
8 a 2007-05-02
9 c 2007-05-02