Question

我在LINQ格式中翻译此查询时遇到问题：

select Version, count(distinct(idUser)) from HistoUsers
group by Version

到目前为止我所拥有的是：

public static List<VersionsUsed> GetNumberOfCompaniesUsingEachVersions2()
{
    var foundUsers = (from hu in sdt.DataContext.HistoUsers

                      group hu by new { hu.Version, hu.IdUser } into g
                      select new VersionsUsed { nameVersion = g.Key.Version, NumberOfCompaniesUsingThisVersion = g.Count((g.Key.IdUser).distinct()) });

    return foundUsers.ToList();
}

似乎我在distinct（）上有语法问题谁可以帮我这个事？提前谢谢

Answer 1

from hu in sdt.DataContext.HistoUsers
group hu by new { hu.Version, hu.IdUser } into g
select new VersionsUsed 
 {  
   nameVersion = g.Key.Version, 
   NumberOfCompaniesUsingThisVersion = g.Select(c=>c.IdUser).Distinct().Count() 
 }

Answer 2

您可以使用LINQER：它从等效的SQL语句生成LINQ语句。您可以从http://www.sqltolinq.com/downloads下载10天试用版。

Answer 3

也许是这样的：

select new VersionsUsed 
        { 
            nameVersion = g.Key.Version, 
            NumberOfCompaniesUsingThisVersion = g.Select(a=>a.IdUser).Distinct().Count()) 
        };

Answer 4

你的独特陈述必须是这样的： Distinct(...)

上面的第一个字母

Answer 5

而不是distinct使用关键字first。它会起作用：

var foundUsers = (from hu in sdt.DataContext.HistoUsers
   group hu by new { hu.Version, hu.IdUser } into g
   select new VersionsUsed { nameVersion = g.Key.Version, NumberOfCompaniesUsingThisVersion = g.Count((g.Key.IdUser).First()) });
return foundUsers.ToList();

在LINQ中有所区别

5 个答案: