C# 林奇集团；多列求和查询

我的数据库中有10列，如

var fpslist = db.FPSinformations.Where(x => x.Godown_Code != null && x.Godown_Code == godownid).ToList();
        var data1 = fpslist.GroupBy(x => x.Ration_Card_Type1)
            .Select(x => new
            {
                CardType_Name = x.Key,
                CardType_Count = x.Sum(y => y.Ration_Card_Count1)
            }).ToList();
        var data2 = fpslist.GroupBy(x => x.Ration_Card_Type2)
            .Select(x => new
            {
                CardType_Name = x.Key,
                CardType_Count = x.Sum(y => y.Ration_Card_Count2)
            }).ToList();
        var data3 = fpslist.GroupBy(x => x.Ration_Card_Type3)
            .Select(x => new
            {
                CardType_Name = x.Key,
                CardType_Count = x.Sum(y => y.Ration_Card_Count3)
            }).ToList();
        var data4 = fpslist.GroupBy(x => x.Ration_Card_Type4)
            .Select(x => new
            {
                CardType_Name = x.Key,
                CardType_Count = x.Sum(y => y.Ration_Card_Count4)
            }).ToList();
        var data5 = fpslist.GroupBy(x => x.Ration_Card_Type5)
            .Select(x => new
            {
                CardType_Name = x.Key,
                CardType_Count = x.Sum(y => y.Ration_Card_Count5)
            }).ToList();

        var GodownRCCount = data1.Where(x => x.CardType_Name != null).ToList();
        var GodownRCCounts = GodownRCCount;
        GodownRCCount = data2.Where(x => x.CardType_Name != null).ToList();
        GodownRCCounts.AddRange(GodownRCCount);
        GodownRCCount = data3.Where(x => x.CardType_Name != null).ToList();
        GodownRCCounts.AddRange(GodownRCCount);
        GodownRCCount = data4.Where(x => x.CardType_Name != null).ToList();
        GodownRCCounts.AddRange(GodownRCCount);
        GodownRCCount = data5.Where(x => x.CardType_Name != null).ToList();
        GodownRCCounts.AddRange(GodownRCCount);

现在我想从它的类型中得到定量卡计数和它的类型之和

预期输出：

Ration_Card_Type1
Ration_card_count1
Ration_Card_Type2
Ration_card_count2
Ration_Card_Type3
Ration_card_count3
Ration_Card_Type4
Ration_card_count4
Ration_Card_Type5
Ration_card_count5

上面的代码工作得很好，但我想以最大可能的方式对其进行优化，因为这将在一个循环中，并且有大约150万条记录

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谢谢

您可以使用SQL重写相同的查询并放置一些索引（性能）：

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我不确定，但这个查询让我想到了UNPIVOT也许你也可以朝这个方向进行调查。

Union应该比AddRange运行得更快！ 您可以尝试以下操作：

SELECT Ration_Card_Type = Ration_Card_Type1, Ration_Card_Count = sum(Ration_card_count1)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type1
UNION
SELECT Ration_Card_Type = Ration_Card_Type2, Ration_Card_Count = sum(Ration_card_count2)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type2
UNION
SELECT Ration_Card_Type = Ration_Card_Type3, Ration_Card_Count = sum(Ration_card_count3)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type3
UNION
SELECT Ration_Card_Type = Ration_Card_Type4, Ration_Card_Count = sum(Ration_card_count4)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type4
UNION
SELECT Ration_Card_Type = Ration_Card_Type5, Ration_Card_Count = sum(Ration_card_count5)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type5

总的来说，我会和托马斯一起去！

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数据库分组对我来说要好得多，因为您获取的是聚合所需的数据，因此通过网络传输的数据要少得多

您可以尝试Union，但如果您关心性能，可能需要编写SQL查询模式未规范化。为什么不创建一个带有

TypeId

和

Count

的表，另一个用于

TypeId

和

TypeName

？这可能会使您的其他查询更快/更简单。从何处开始。。。这里大约有10种明显的代码气味。首先需要更改数据库架构。也。。。1） “擦干”你的代码2）你为什么到处都有收费表？在这上面运行一个查询分析器-冗长的事情将会发生。3） 为什么有5个“类型”作为单独的列？当你介绍type6时会发生什么？4） var GodownRCCounts=GodownRCCount；——奇怪和困惑。。。5） 即使分开重复的列是个好主意，你的代码不是对你喊着“使用循环”吗？6） 如果你需要用“1500万记录”来优化某些东西，你会遇到更大的问题。阿里吉特穆克吉——这正是我要说的。架构未规范化。请阅读有关数据库中普通表单的更多信息。所有行都有所有值吗？在这种情况下，查询中仍将检查空列。就像@JonRea建议的那样，当你有一张配给卡时会发生什么？你必须更新整个表格。@JamesZ nice edit:）我猜你的意思是

Concat

而不是

Union

是的！在这种情况下，Concat将比Union更快，因为您知道列表包含唯一的值。当您在SQL中执行“UNIONALL”时，如果这是从SQL完成的

SELECT Ration_Card_Type = Ration_Card_Type1, Ration_Card_Count = sum(Ration_card_count1)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type1
UNION
SELECT Ration_Card_Type = Ration_Card_Type2, Ration_Card_Count = sum(Ration_card_count2)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type2
UNION
SELECT Ration_Card_Type = Ration_Card_Type3, Ration_Card_Count = sum(Ration_card_count3)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type3
UNION
SELECT Ration_Card_Type = Ration_Card_Type4, Ration_Card_Count = sum(Ration_card_count4)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type4
UNION
SELECT Ration_Card_Type = Ration_Card_Type5, Ration_Card_Count = sum(Ration_card_count5)
FROM 
   FPSinformations
GROUP BY
    Ration_Card_Type5

var data = (from g in fpslist.GroupBy(x => x.Ration_Card_Type1).Select(x => new
            {
                CardType_Name = x.Key,
                CardType_Count = x.Sum(y => y.Ration_Card_Count1)
            }).Union(
              fpslist.GroupBy(x => x.Ration_Card_Type2).Select(x => new
              {
                  CardType_Name = x.Key,
                  CardType_Count = x.Sum(y => y.Ration_Card_Count2)
              })).Union(
              fpslist.GroupBy(x => x.Ration_Card_Type3).Select(x => new
              {
                  CardType_Name = x.Key,
                  CardType_Count = x.Sum(y => y.Ration_Card_Count3)
              })).Union(
             fpslist.GroupBy(x => x.Ration_Card_Type4).Select(x => new
             {
                 CardType_Name = x.Key,
                 CardType_Count = x.Sum(y => y.Ration_Card_Count4)
             })).Union(
             fpslist.GroupBy(x => x.Ration_Card_Type5).Select(x => new
             {
                 CardType_Name = x.Key,
                 CardType_Count = x.Sum(y => y.Ration_Card_Count5)
             }))
                        select g).ToList();