左连接Linq到实体的Vb.net
我无法弄清楚linq到实体查询语法。我的问题是，如果Calls表的值为null然后出现注释，我想做一些类似于左连接的东西来从Calls表中获取'all'行。
我试图将它分组，但我无法弄清楚写它的正确方法。
Dim TicketQuery As ObjectQuery = From c In EnData.Customer _
Join t In EnData.Calls On t.CustomerID Equals c.CustomerID _
Join Status In EnData.Lists On t.Status Equals Status.ListValue _
Join Project In EnData.Lists On t.Project Equals Project.ListValue _
Join Priorty In EnData.Lists On t.Priority Equals Priorty.ListValue _
Where c.Status > -1 And t.Status > -1 And Status.ListType = 1 And Project.ListType = 3 And Priorty.ListType = 2 _
Select New With {c.CustName, t.CallID, t.CallDate, t.CallTime, t.Description, Key .Status = Status.ListText, Key .Project = Project.ListText, t.DateModified, Key .Priority = Priorty.ListText}
没有找到相关结果
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粟痢凰副
Public Sub Linq105() Dim categories() = {"Beverages", "Condiments", "Vegetables", "Dairy Products", "Seafood"} Dim productList = GetProductList() Dim query = From c In categories _ Group Join p In productList On c Equals p.Category Into Group _ From p In Group.DefaultIfEmpty() _ Select Category = c, ProductName = If(p Is Nothing, "(No products)", p.ProductName) For Each v In query Console.WriteLine(v.ProductName + ": " + v.Category) Next End Sub熊融炭臀陛
Dim q = (From item In _userProfileRepository.Table Let Country = (From p In _countryRepository.Table Where p.CountryId = item.CurrentLocationCountry Select p.Name).FirstOrDefault Let State = (From p In _stateRepository.Table Where p.CountryId = item.CurrentLocationCountry Select p.Name).FirstOrDefault Let City = (From p In _stateRepository.Table Where p.CountryId = item.CurrentLocationCountry Select p.Name).FirstOrDefault Where item.UserId = item.ProfileId.ToString)Dim q2 = (From p In q Group p By p.Country, p.State, p.City Into Group Select New With { .Country = Country, .State = State, .City = City, .Count = Group.Count }).ToList()