Question

我很抱歉这个问题，但我不能从DateTime开始。例如：如果我有日期"10.10.2016 7:00", 10.10.2016 10:00"，我只需要时间在“6:00”和“8:00”之间的行。接下来是我的代码返回错误："can not use TimeOfDay ",请帮助我

ds.TrafficJamMorning = (from row in orderQuery
                        where row.AcceptedTime.TimeOfDay >= new TimeSpan(6, 30, 0) &&
                        row.AcceptedTime.TimeOfDay <= new TimeSpan(9, 30, 0)
                        group row by row.AcceptedTime.Date
                        into grp
                        select new TrafficJamPeriodInfo
                        {
                             CurrentDateTime = grp.Key,
                             ReceptionCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Reception),
                             InternetCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Internet),
                             ExchangeSystemCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.ExchangeSystem)
                        }).ToList();

Answer 1

TimeOfDay linq提供程序不支持它，它不知道如何将其解析为sql。请改为使用DbFunctions.CreateTime：

还在linq查询之前实例化时间跨度，这样每次都不会实例化新对象

var startTime = new TimeSpan(6, 30, 0);
var endTime = new TimeSpan(9, 30, 0);

var result = (from row in orderQuery
              let time = DbFunctions.CreateTime(row.AcceptedTime.Hour, row.AcceptedTime.Minute, row.AcceptedTime.Second)
              where time  >= startTime &&
                    time  <= endTime
              group row by DbFunctions.TruncateTime(row.AcceptedTime) into grp
              select new TrafficJamPeriodInfo
              {
                   CurrentDateTime = grp.Key,
                   ReceptionCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Reception),
                   InternetCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Internet),
                   ExchangeSystemCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.ExchangeSystem)
              }).ToList();

再看一下这个问题 - 如果您只想检查它是否在2小时之间，那么请使用Hour属性（如果要检查示例，这将不好写Hour和Minues，在这种情况下，我会提出我的第一个建议）：

var result = (from row in orderQuery
              where row.AcceptedTime.Hour >= 6
                    row.AcceptedTime.Hour < 8
              group row by DbFunctions.TruncateTime(row.AcceptedTime) into grp
              select new TrafficJamPeriodInfo
              {
                   CurrentDateTime = grp.Key,
                   ReceptionCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Reception),
                   InternetCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Internet),
                   ExchangeSystemCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.ExchangeSystem)
              }).ToList();

Answer 2

我遇到了类似的问题。

您可以改为比较日期部分。

其中row.Year＆gt; s.Year＆amp;＆amp; r.Month＆gt; s.Month＆amp;＆amp; row.Day＆gt; s.Day

Answer 3

我在IQueryable上使用以下where子句：

var query = dbContext.GetAllItems().AsQueryable();

//... other filters

if(MusBeBetween6and8){
    query = query.Where(item => item.AcceptedTime.Hour > 6 && item.AcceptedTime.Hour < 8);
}

//... other filters

return query.ToList();

希望它有所帮助。这也适用于Oracle + Odac。

Answer 4

ds.TrafficJamMorning = (from row in orderQuery
                        where 
                            DbFunctions.DiffMinutes( DbFunctions.TruncateTime(row.AcceptedTime), row.AcceptedTime) >= 6 * 60 + 30 &&
                            DbFunctions.DiffMinutes( DbFunctions.TruncateTime(row.AcceptedTime), row.AcceptedTime) <= 9 * 60 + 30
                        group row by DbFunctions.TruncateTime(row.AcceptedTime)
                        into grp
                        select new TrafficJamPeriodInfo
                        {
                            CurrentDateTime = grp.Key,
                            ReceptionCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Reception),
                            InternetCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.Internet),
                            ExchangeSystemCount = grp.Count(r => r.OrderOriginId == (int)OrderOrigin.ExchangeSystem)
                        }).ToList();

实体框架按时间过滤数据

4 个答案: