需要linq查询复杂情况 [英] Need a linq query for the complex situation

问题描述

我有一个场景。我的桌子由三个小组组成。对于每个条目，必须有两行类型ID不同。

Hi I have a scenario. My table consists of three cols. For every entry there must be two rows with type id different.

GrpId    type id       entryID
------------------------------
10         1           1
-1         2           1
11         1           2
12         2           2
10         1           3
-1         2           3
10         1           4
-1         2           4
23         1           5
-1         2           5
24         1           6
-1         2           6
10         1           7
-1         2           7
10         1           8
-1         2           8

我需要一个linq查询

我有两个条件

当类型id应该是1而grpid应该是10得到条目id

结果应该是那个条目id我需要grp id -1并输入id 2



结果应该是：

I need a single linq query
I have two conditions
when type id should be 1 and grpid should be 10 get entry id
result should be for that entry id i need grp id -1 and type id 2

Result should be:

GrpId    type id       entryID
------------------------------
-1         2           1
-1         2           3
-1         2           4
-1         2           7
-1         2           8

我尝试了什么：



我尝试过分组，但有些地方但没有工作

What I have tried:

I tried group by and some where but didn't work

推荐答案

看看例子：

Take a look at example:

DataTable dt = new DataTable();
dt.Columns.Add(new DataColumn("GrpId", typeof(int)));
dt.Columns.Add(new DataColumn("type id", typeof(int)));
dt.Columns.Add(new DataColumn("entryID", typeof(int)));

dt.Rows.Add(new object[]{10, 1, 1});
dt.Rows.Add(new object[]{-1, 2, 1});
dt.Rows.Add(new object[]{11, 1, 2});
dt.Rows.Add(new object[]{12, 2, 2});
dt.Rows.Add(new object[]{10, 1, 3});
dt.Rows.Add(new object[]{-1, 2, 3});
dt.Rows.Add(new object[]{10, 1, 4});
dt.Rows.Add(new object[]{-1, 2, 4});
dt.Rows.Add(new object[]{23, 1, 5});
dt.Rows.Add(new object[]{-1, 2, 5});
dt.Rows.Add(new object[]{24, 1, 6});
dt.Rows.Add(new object[]{-1, 2, 6});
dt.Rows.Add(new object[]{10, 1, 7});
dt.Rows.Add(new object[]{-1, 2, 7});
dt.Rows.Add(new object[]{10, 1, 8});
dt.Rows.Add(new object[]{-1, 2, 8});

//get entries
var entries = dt.AsEnumerable()
	.Where(x=>x.Field<int>("GrpId")==10)
	.Select(x=>x.Field<int>("entryID"))
	.ToList();
//get result
var result = dt.AsEnumerable()
	.Where(x=> x.Field<int>("GrpId")==-1 && 
			x.Field<int>("type id")==2 && 
			entries.Any(y=>y==x.Field<int>("entryID")))
	.ToList();

祝你好运！

Good luck!

这篇关于需要linq查询复杂情况的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！