一、在使用Linq时，想要比较字符串类型的日期时，参考以下：
SQL语句：
1）select * from TableName where StartTime > '2015-04-08'
2）select * from TableName where StartTime >= '2015-04-08'
3）select * from TableName where StartTime < '2015-04-08'
4）select * from TableName where StartTime <= '2015-04-08'
lambda表达式写法：
）.Where(a => a.StartTime.CompareTo('2015-04-08') > )
）.Where(a => a.StartTime.CompareTo('2015-04-08') >= )
）.Where(a => a.StartTime.CompareTo('2015-04-08') < )
）.Where(a => a.StartTime.CompareTo('2015-04-08') <= )
更规范的写法：
）.Where(a => String.Compare(a.StartTime, '2015-04-08', StringComparison.Ordinal) > )
）.Where(a => String.Compare(a.StartTime, '2015-04-08', StringComparison.Ordinal) >= )
）.Where(a => String.Compare(a.StartTime, '2015-04-08', StringComparison.Ordinal) < )
）.Where(a => String.Compare(a.StartTime, '2015-04-08', StringComparison.Ordinal) <= )
二、但是，又遇到Linq延时查询的问题。