How to aggregate with comma using group by

Question

0.00/5 (No votes)

See more:

I have TableDE class that IdFirst, IdSecond and Name

What I have tried:

C#

<pre>                
var userEntityGroups = TableDE.GroupBy(x => new { x.IdFirst, x.IdSecond})
.OrderBy(g => g.Key.IdFirst).ThenBy(g => g.Key.IdSecond)
.Select(g => new
{
     IdFirst = g.Key.IdFirst,
     IdSecond= g.Key.IdSecond,
     TableDE= g.OrderBy(x => x.Name)
});

then i return Ok(userEntityGroups) //webApi response

Now when i debug user entity groups has 2 records
[0] where this has IdFirst, IdSecond and TableDE
[1] Also where this has IdFirst, IdSecond and TableDE

now in TableDE of [0] it has 2 records [0] and [1] where IdFirst and IdSecond are similar but name field for each one is different

Also in TableDE of [1] it has 2 records [0] and [1] where IdFirst and IdSecond are similar but name field for each one is different

I don't want return userEntityGroups to return 4 records i want it to only return 2 records

right now this is what i'm getting

IdFirst=1, IdSecond=1, Name=name11
IdFirst=1, IdSecond=1, Name=name12
IdFirst=2, IdSecond=2, Name=name21
IdFirst=2, IdSecond=2, Name=name22

This is what i want

IdFirst=1, IdSecond=1, Name=name11,name12
IdFirst=2, IdSecond=2, Name=name21,name22

Posted 15-Apr-20 11:54am

Member 14800672

Updated 15-Apr-20 23:14pm

Maciej Los

v5

Add a Solution

Comments

Maciej Los 16-Apr-20 4:09am

What's your input data?

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Maciej Los · Answer 1 · 2020-04-15T22:27:00

Take a look at below example, which should help in resolving an issue.

C#

//LinqPad rules!
void Main()
{
	List<TableDE> data = new List<TableDE>()
	{
		new TableDE(){IdFirst=1, IdSecond=1, Name="name11"},
		new TableDE(){IdFirst=1, IdSecond=1, Name="name12"},
		new TableDE(){IdFirst=2, IdSecond=2, Name="name21"},
		new TableDE(){IdFirst=2, IdSecond=2, Name="name22"},
		new TableDE(){IdFirst=3, IdSecond=3, Name="name31"},
		new TableDE(){IdFirst=1, IdSecond=2, Name="name1221"}
	};

	var result = data
		.GroupBy(x=> new{ Id1 =  x.IdFirst,  Id2 = x.IdSecond})
		.Select(grp=> new
		{
			IdFirst = grp.Key.Id1,
			IdSecond = grp.Key.Id2,
			Names = string.Join(",", grp.OrderBy(y=>y.Name).Select(y=>y.Name)),
		})
		.OrderBy(x=>x.IdFirst)
		.ThenBy(x=>x.IdSecond)
		.ToList();
	result.Dump();

}

// Define other methods and classes here
public class TableDE
{
	public int IdFirst { get; set; }
	public int IdSecond { get; set; }
	public string Name { get; set; }
}

Result:

IdFirst IdSecond Names
1       1        name11,name12 
1       2        name1221 
2       2        name21,name22 
3       3        name31