将linq中的字符串聚合或连接到SQL查询（SQL Server）

给出一个像这样的表

ID | Name | City 1 | X | Y 2 | Z | Y 3 | W | K 

我想产生一个像这样的结果

 ID | Description 1 | Y (X, Z) 3 | K (W) 

我尝试过类似的东西

 From C In Clients Group C By C.ID, C.City _ Into G = Group Select New With {.ID = ID, .Description = City & _ " (" & (From C In Clients Select C.Name).Aggregate(Function(X, Y) X & ", " & Y) & ")"} 

这给了我一个错误“不支持查询运算符’聚合’。” 也试过了

 From C In Clients Group C By C.ID, C.City _ Into G = Group Select New With {.ID = ID, .Description = City & _ " (" & String.Join((From C In Clients Select C.Name).ToArray, ", ") & ")"} 

这给了我错误“没有支持的SQL转换”

那么，我该怎么做呢？

Answer 1

我在C＃中攻击了它，它似乎给你想要的东西。 我会把翻译留给VB给你。

 var clients = from c in context.Clients group c by c.City into cities select new { ID = cities.First().ID, City = cities.Key, Names = string.Join(",", (from n in cities select n.Name).ToArray()) }; foreach (var c in clients) { Console.WriteLine(string.Format("{0}| {1} ({2})", c.ID, c.City, c.Names)); } 

Answer 2

该错误意味着您无法在TSQL中对SQL Server执行LINQ操作，就像您编写的那样。

要实现您的目标，您必须尽可能多地选择/评估基础数据，然后在第二步中执行聚合。 两步或更多步骤过程并不理想，但可以完成。