linq 计数优化

发布于 2024-10-25 01:47:34 字数 423 浏览 1 评论 0原文

我正在编写一个 linq 查询，我想知道我做得是否正确：我传递了 2 个参数，TheDate 和 UserID

Var Output = from c in in MyDC.Table1
  where c.Datetime.Date == TheDate.Date
  where c.UserID == TheUserID
  select new MyMode()
  {
    Var1 = (from c1 in MyDC.Table1
            where c.ID == c1.ID
            select c1.ID).Count()
    Var2 = ...

  }

我想我应该能够对 Var1 进行计数，而无需返回到原来的MyDC，但现在这就是我所拥有的。让我知道是否有更好的方法。

谢谢。

原文

I'm writing a linq query and I'm wondering if I'm doing it right: I'm passing in 2 parameters, TheDate and UserID

Var Output = from c in in MyDC.Table1
  where c.Datetime.Date == TheDate.Date
  where c.UserID == TheUserID
  select new MyMode()
  {
    Var1 = (from c1 in MyDC.Table1
            where c.ID == c1.ID
            select c1.ID).Count()
    Var2 = ...

  }

I'm thinking I should be able to do the count for Var1 without going back to the original MyDC but for now that's what I have.
Let me know if there's a better way to do it.

Thanks.

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水中月 2024-11-01 01:47:34

这难道不等于：

Var1 = c.Count()

您也需要对某些值进行分组吗？

Wouldn't that be the same as:

Var1 = c.Count()

Are you needing to group on some value, too?

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梦晓ヶ微光ヅ倾城 2024-11-01 01:47:34

计数是使用基于方法的语法的覆盖。

var defaults = new[] { "zero", "one", "two", "three", "four" };

var abc = defaults.Select((o,i) => i);
abc.Dump();

输出：IEnumerable（5 项）
0
1
2
3
4

o 是对象，i 是索引。我通常使用方法语法，所以我不确定对其的转换。

The count is an override using method-based syntax.

var defaults = new[] { "zero", "one", "two", "three", "four" };

var abc = defaults.Select((o,i) => i);
abc.Dump();

outputs: IEnumerable (5 items)
0
1
2
3
4

o is the object and i is the index. I usually use method syntax so I'm not sure on the conversion to it.

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二智少女猫性小仙女 2024-11-01 01:47:34

var result = from c in MyDC.Table1
             where c.Datetime.Date == TheDate.Date
             && c.UserID == TheUserID
             group c by c.ID into g
             select new
             {
                 Var1 = g.Count()
             };

var result = from c in MyDC.Table1
             where c.Datetime.Date == TheDate.Date
             && c.UserID == TheUserID
             group c by c.ID into g
             select new
             {
                 Var1 = g.Count()
             };

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