Linq查询与多个计数

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这就是我想做的事：

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这里是我的LINQ查询：

var query = from a in table 
      where a.Country.Equals("USA") 
      group a by a.Product_brand into grp 
      select new 
      { 
       Product_brand = grp.key.Product_brand, 
       Country = grp.Key.Country, 
       Black = grp.Count(a => a.Black=="Yes"), 
       White = grp.Count(a => a.White=="Yes"), 
       Red = grp.Count(a=> a.Red=="Yes"), 
       Green = grp.Count(a=> a.Green=="Yes") 
      }

我不知道我的问题有什么问题RY，我不断收到这样的信息：

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替代解决方案：

SQL查询：

SELECT [Product brand], Country, 
sum(case when [Black] = 'Yes' then 1 else 0 end) as Black, 
sum(case when [White] = 'Yes' then 1 else 0 end) as White, 
sum(case when [Red] = 'Yes' then 1 else 0 end) as Red, 
sum(case when [Green] = 'Yes' then 1 else 0 end) as Green, 
FROM   dbo.Table 

group by [Product brand], Country

来源

2013-08-20 Zack09

这似乎没有在linq的一些问题，也许它在你的连接。 –

您的服务器已关闭或无法访问？你的查询看起来很好：只要你的表的大小不在数十亿行中，你就应该很快得到你的结果。 – dasblinkenlight

服务器肯定没有关闭，我只是测试了连接它正在工作 – Zack09

，如果你想要的工作像你要组由两个字段：

var query = from a in table 
     where a.Country.Equals("USA") 
     group a by new {a.Product_brand, a.Country} into grp 
     select new 
     { 
      Product_brand = grp.key.Product_brand, 
      Country = grp.Key.Country, 
      Black = grp.Count(a => a.Black=="Yes"), 
      White = grp.Count(a => a.White=="Yes"), 
      Red = grp.Count(a=> a.Red=="Yes"), 
      Green = grp.Count(a=> a.Green=="Yes") 
     }

来源

2013-08-26 21:22:00

在VB.Net代码是像那

Dim query=(from a in table 
where a.Country = "USA" 
group a by a.Product_brand,a.country into grp = group _ 
select new with 
{ 
    .Product_brand=Product_brand, 
    .country=country, 
    .Black = grp.Count(Function(a) a.Black="Yes"), 
    .White = grp.Count(Function(a) a.White="Yes"), 
    .Red = grp.Count(Function(a) a.Red="Yes"), 
    .Green = grp.Count(Function(a) a.Green="Yes") 
})

来源

2013-09-06 07:55:24

Linq查询与多个计数

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