Question

请考虑以下表格：

Organization           State          Year          Month        Value
----------------------------------------------------------------------
   O1                   NY             2017          1            1
   01                   WA             2017          1            2
   01                   SA             2017          1            3
   O1                   NY             2017          2            4
   01                   WA             2017          2            5
   01                   SA             2017          2            6
   O2                   NY             2015          9            7
   02                   WA             2015          9            8
   02                   SA             2015          9            9
   O2                   NY             2016          1            10
   02                   WA             2016          1            11
   02                   SA             2016          1            12
   O3                   NY             2017          8            13
   03                   WA             2017          8            14
   03                   SA             2017          8            15

我要创建此结果：

Organization           Year          Month        Sum
------------------------------------------------------
    01                 2017            2           15
    02                 2016            1           33
    03                 2017            8           42

我想对最新的Year, Month进行分组并计算总和。在上面的示例中，组织01拥有2个期间的数据，但我想按最新期间分组。

更新1）

var query = from o in MyList
            group o by new {c.Organization, c.Year , c.Month} int grp
            select new 
            { 
                grp.Key.Organization, 
                grp.Key.Year, 
                grp.Key.Month, 
                grp.Sum() 
            };

Answer 1

请尝试以下查询：

class Program
{
    static void Main(string[] args)
    {           

        var results = (from o in MyList
                       group o by new { o.Organization } into g
                       select new
                       {
                           Org_Id = g.Key.Organization,
                           Year = g.Select(x => x.Year)
                                   .Max(),
                           Month = g.Where(x => x.Year == g.Select(y => y.Year).Max())
                                    .Select(z => z.Month)
                                    .Max(),
                           Sum = g.Where(x => x.Month == g.Where(y => y.Year == g.Select(z => z.Year).Max())
                                                          .Select(y => y.Month)
                                                          .Max())
                                  .Select(z => z.Value)
                                  .Sum()
                       }).ToList();

        results.ForEach(x => Console.WriteLine($"Org_Id: {x.Org_Id} \t Year: {x.Year} \t Month: {x.Month} \t Sum: {x.Sum}"));

        Console.ReadLine();
    }
}

我们在查询中所做的事情

1）按Organization分组

2）Org_Id：作为您组的密钥

3）Year：从组中选择Max年。

4）Month：通过从组中选择年份的Max来选择月份的Max。

5）Sum：通过从组中选择年份Max的月份的Max得出的总和。

输出：

上述查询的SQL：

SELECT [t1].[Organization] AS [Org_Id], (
    SELECT MAX([t2].[Year])
    FROM [Org] AS [t2]
    WHERE (([t1].[Organization] IS NULL) AND ([t2].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t2].[Organization] IS NOT NULL) AND ((([t1].[Organization] IS NULL) AND ([t2].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t2].[Organization] IS NOT NULL) AND ([t1].[Organization] = [t2].[Organization]))))
    ) AS [Year], (
    SELECT MAX([t3].[Month])
    FROM [Org] AS [t3]
    WHERE ([t3].[Year] = ((
        SELECT MAX([t4].[Year])
        FROM [Org] AS [t4]
        WHERE (([t1].[Organization] IS NULL) AND ([t4].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t4].[Organization] IS NOT NULL) AND ((([t1].[Organization] IS NULL) AND ([t4].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t4].[Organization] IS NOT NULL) AND ([t1].[Organization] = [t4].[Organization]))))
        ))) AND ((([t1].[Organization] IS NULL) AND ([t3].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t3].[Organization] IS NOT NULL) AND ((([t1].[Organization] IS NULL) AND ([t3].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t3].[Organization] IS NOT NULL) AND ([t1].[Organization] = [t3].[Organization])))))
    ) AS [Month], (
    SELECT SUM([t5].[Value])
    FROM [Org] AS [t5]
    WHERE ([t5].[Month] = ((
        SELECT MAX([t6].[Month])
        FROM [Org] AS [t6]
        WHERE ([t6].[Year] = ((
            SELECT MAX([t7].[Year])
            FROM [Org] AS [t7]
            WHERE (([t1].[Organization] IS NULL) AND ([t7].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t7].[Organization] IS NOT NULL) AND ((([t1].[Organization] IS NULL) AND ([t7].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t7].[Organization] IS NOT NULL) AND ([t1].[Organization] = [t7].[Organization]))))
            ))) AND ((([t1].[Organization] IS NULL) AND ([t6].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t6].[Organization] IS NOT NULL) AND ((([t1].[Organization] IS NULL) AND ([t6].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t6].[Organization] IS NOT NULL) AND ([t1].[Organization] = [t6].[Organization])))))
        ))) AND ((([t1].[Organization] IS NULL) AND ([t5].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t5].[Organization] IS NOT NULL) AND ((([t1].[Organization] IS NULL) AND ([t5].[Organization] IS NULL)) OR (([t1].[Organization] IS NOT NULL) AND ([t5].[Organization] IS NOT NULL) AND ([t1].[Organization] = [t5].[Organization])))))
    ) AS [Sum]
FROM (
    SELECT [t0].[Organization]
    FROM [Org] AS [t0]
    GROUP BY [t0].[Organization]
    ) AS [t1]

输出：

Answer 2

我认为您获取输出的逻辑是错误的。我从“输出”分组中看到的内容分两个步骤完成

第1步

Group By Organization, State, MAX(Year) AS Year, MAX(Month) AS Month, MAX(Value) As Value

第二步

Group By Organization, MAX(Year) AS Year, MAX(Month) AS Month, SUM(Value) As Value

最终输出具有组织在每个州下的最大值的总和。

如果我的假设是正确的，那么您将能够为此编写LINQ查询

按最新组申请

2 个答案: