我正在尝试使用LINQ查询此表:
这就是我想要做的事情:
这是我的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")
}
我不知道我的查询有什么问题,我不断收到这条消息:
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
答案 0 :(得分:3)
如果您希望它起作用,您必须按两个字段分组 类似的东西:
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")
}
答案 1 :(得分:0)
在VB.Net代码中就是那样
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")
})