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Min的合并DateOnly和TimeSpan值 d.RequestedDate [DateOnly] + d.RequestedDateTimeFrom [TimeSpan]在DB中看起来像这样：

RequestedDate : 2013-06-01
RequestedDateTimeFrom : 13:50

这不编译：

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，这实际上解决了我的主要问题，即如果有更多的日期时间同时具有相同的日期和时间值，我将通过thrid Sequence列进行比较。所以归结为简单排序：

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（并且未经测试，说实话），但我会尝试在TimeSpan上使用SqlFunctions.DateAdd的符号化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.AddHours和EntityFunctions.AddMinutes代替SqlFunctions.DateAdd）

DateTime的聚合在日期和时间列中拆分

1 个答案: