1， desc：降序，明天今天昨天，zyx...cba，.....321
sql语句：select * from SC_BackDiggingInfo where WriteDate<='2013-08-31' order by WriteDate desc
例如：
| WriteDate |
| 2013-08-28 00:00:00.000 |
| 2013-08-27 00:00:00.000 |
| 2013-08-26 00:00:00.000 |
| 2013-08-25 00:00:00.000 |
| 2013-08-24 00:00:00.000 |
| 2013-08-23 00:00:00.000 |
| 2013-08-22 00:00:00.000 |
2， asc： 升序，昨天今天明天,abc...xyz,123......
sql语句：select * from SC_BackDiggingInfo where WriteDate<='2013-08-31' order by WriteDate asc
例如：
| WriteDate |
| 2013-08-22 00:00:00.000 |
| 2013-08-23 00:00:00.000 |
| 2013-08-24 00:00:00.000 |
| 2013-08-25 00:00:00.000 |
| 2013-08-26 00:00:00.000 |
| 2013-08-27 00:00:00.000 |
| 2013-08-28 00:00:00.000 |