读取一段日期（日期为字符型）内的数据的总和，sql语句该怎么写？
数据库如下：
DATETIME S5
2011-02-07 8:00:00
2011-02-08 8:00:00
2011-02-09 8:00:00
2011-02-10 8:00:0020
2011-03-11 8:00:00
2011-03-12 8:00:0058
2011-03-13 8:00:00
DATETIME为字符型，s5为整形，我想统计2011-02-09 8:00:00到2011-03-13 8:00:00之间的总和，sql语句该怎么写？


[解决办法]
select sum(S5) from 数据表名 where DATETIME >= '2011-02-09 8:00:00'
and DATETIME <= '2011-03-13 8:00:00'

[解决办法]
DATETIME保存的格式最好是这样:yyyy-mm-dd hh:mm:ss

select sum(isnull(S5,0)) from t where DATETIME>='2011-02-09 08:00:00'
and DATETIME<='2011-03-13 08:00:00'