c# - 日期和时间列中日期时间拆分的聚合

Question

我有以下查询

from booking in query
join ba in Context.BookingAddresses on booking.Id equals ba.BookingId into collections
let firstCollection = (from d in collections where d.AddressType == BookingAddressType.Collection select d.RequestedDate).Min()                            
where
EntityFunctions.TruncateTime(queryArgs.DateFrom.Value) <= EntityFunctions.TruncateTime(firstCollection) &&
EntityFunctions.TruncateTime(queryArgs.DateTo.Value) >= EntityFunctions.TruncateTime(firstCollection)
select booking;

在 let 子句中，我实际上需要合并的 DateOnly 和 TimeSpan 值 d.RequestedDate [DateOnly] + d.RequestedDateTimeFrom [TimeSpan] 的最小值，在 DB 中看起来像这样：

申请日期：2013-06-01
RequestedDateTimeFrom : 13:50

这不会编译：

let firstCollection = (from d in collections where d.AddressType == BookingAddressType.Collection select d.RequestedDate + d.RequestedDateTimeFrom)

编辑：与此同时，我想到了一种不同的方法，这实际上可以解决我的主要问题，即，如果有更多日期和时间值相同的日期时间，我将通过第三个序列列进行比较。所以它归结为简单的排序，如下所示：

from booking in query
join ba in Context.BookingAddresses on booking.Id equals ba.BookingId into collections
let firstCollection = collections.OrderBy(c => c.RequestedDate).ThenBy(c => c.RequestedFromTime).ThenBy(c => c.Sequence).FirstOrDefault()
//(from d in collections where d.AddressType == BookingAddressType.Collection select d.RequestedDate).Min()
where
EntityFunctions.TruncateTime(queryArgs.DateFrom.Value) <= EntityFunctions.TruncateTime(firstCollection.RequestedDate) &&
EntityFunctions.TruncateTime(queryArgs.DateTo.Value) >= EntityFunctions.TruncateTime(firstCollection.RequestedDate)
select booking;

Answer 1

这可能不是最优雅的方式（老实说，未经测试），但我会尝试在 TimeSpan 上使用SqlFunctions.DateAdd 和SqlFunctions.DatePart

SqlFunctions.DateAdd("hh", 
                      SqlFunctions.DatePart("hh", d.RequestedDateTimeFrom), 
                      SqlFunctions.DateAdd("mi", 
                                            SqlFunctions.DatePart("mi", d.RequestedDateTimeFrom), 
                                            d.RequestedDate);

（您也可以使用EntityFunctions.AddHoursandEntityFunctions.AddMinutes代替SqlFunctions.DateAdd）