Sql Server - Linq , SQL时间相关 - SQL日期,时间比较

SQL Server 中时间比较

例子:

select count(*) from table where DATEDIFF ([second], ‘2004-09-18

00:00:18’, ‘2004-09-18 00:00:19’) > 0

说明

select DATEDIFF(day, time1 , time2) 对应示例语句如下

　　select DATEDIFF(day, ‘2010-07-23 0:41:18’, ‘2010-07-23 23:41:18’)

　　time1 > time2 为负数;

　　time1 < time2 为正数;

　　[day] :只会比较 2010-07-23 忽略 0:41:18’ 其他同理

以下分别:

年: SELECT DATEDIFF([year],time1 , time2) 返回值： -6 ，说明是后减前 与 mysql

　　月: SELECT DATEDIFF([month], time1 , time2)

　　天: SELECT DATEDIFF([day], time1 , time2)

　　小时: SELECT DATEDIFF([hour], time1 , time2)

　　秒: SELECT DATEDIFF([second], time1 , time2)

Entity Framework（LINQ to Entities）使用日期判断条件Truncate日期函数,类似Convert函数，MYSQL数据库可以直接使用convert(varchar(10),a.cjrq,120)

LINQ to Entities使用日期字段查询，截取日期，不包括时间，测试环境SQL Server2005/2008，Entity Framework4.0

public void TestMethod1()
{
using (var _context = new hotelEntities())
{
var rq = DateTime.Now.Date;
var query = from q in _context.UV_RZJL_RZRY_Single
where EntityFunctions.TruncateTime(q.LDRQ) >=rq
select q;
Assert.Inconclusive(query.Count().ToString());
}
}

//SqlFunctions.DateDiff的函数也可以实现

public void TestMethod1()
{
using (var _context = new hotelEntities())
{
var rq = DateTime.Now.Date;
var query = from q in _context.UV_RZJL_RZRY_Single
where SqlFunctions.DateDiff("day",rq,q.LDRQ)>0
select q;
Assert.Inconclusive(query.Count().ToString());

}
}

***筛选本周数据***

//获取当天的数据
DrawRecordDA _recordDA = new DrawRecordDA();
var query = _recordDA.GetQuery();

//筛选 当天
//query = query.Where(q=>SqlFunctions.DateDiff("day",q.AddTime,DateTime.Now)==0);

//筛选 当天
//  query = query.Where(q=>q.AddTime.Day==DateTime.Now.Day);
//筛选 本周
query = query.Where(q => SqlFunctions.DateDiff("week", q.AddTime, DateTime.Now) == 0);

Console.WriteLine(query.Count());