在最新组上应用分组依据

Question

请考虑这个table:

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

我想创建这个结果：

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 有 2 个时间段的数据，但我想在最近的时间段进行分组。

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

我认为你获取输出的逻辑是错误的。我从输出分组中看到的是分两步完成的

步骤1

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

步骤2

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

最终输出具有组织每个状态下的最大值的总和。

如果我的假设是正确的，那么您将能够为此编写 LINQ 查询

Answer 2

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();
    }
}

我们在查询中做了什么：

1) 按 Organization

分组

2) Org_Id: 作为你组的关键

3) Year: select Max 组年。

4) Month: select Max 月份 selecting Max 组。

5) Sum: select 年 Max 月 Max 组的值总和。

输出：

Sql 对于上述查询：

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：

在最新组上应用分组依据

Apply Group by on latest group

c#

linq

linq-to-entities

group-by