使用Linq进行分组并计数

Question

如何在Linq（VB.NET）中编写此查询？

 select B.Name
 from Company B
 group by B.Name
 having COUNT(1) > 1

- Fernando

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可能是 https://dev59.com/f0nSa4cB1Zd3GeqPKhD_ 的重复问题。 - Michael Freidgeim

Answer 1

像这样：

from c in db.Company
group c by c.Name into grp
where grp.Count() > 1
select grp.Key

或者，使用方法语法：

Company
    .GroupBy(c => c.Name)
    .Where(grp => grp.Count() > 1)
    .Select(grp => grp.Key);

- Thomas Levesque

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感谢提供这两种语法形式！:D - Jess

感谢您提供的解决方案。 - Sudhanshu Pal

简单而准确，谢谢。 - Mohammed Mohammed

Answer 2

如果有人想在VB中实现这个功能（就像我一样并且找不到任何东西），可以参考以下方法：

From c In db.Company 
Select c.Name Group By Name Into Group 
Where Group.Count > 1

- Michael Andrews

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我觉得很难理解为什么在VB中Group By在Select子句之后。 - Arvin

Answer 3

下面的解决方案可能会对您有所帮助。

var unmanagedDownloadcountwithfilter = from count in unmanagedDownloadCount.Where(d =>d.downloaddate >= startDate && d.downloaddate <= endDate)
group count by count.unmanagedassetregistryid into grouped
where grouped.Count() > request.Download
select new
{
   UnmanagedAssetRegistryID = grouped.Key,
   Count = grouped.Count()
};

- Sudhanshu Pal

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这与问题有何关联？ - Gert Arnold