how to write self join in LINQ

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How do we write self join in LINQ? I have tried this:

C#

from coa in GL0_ChartOfAccounts
  join c in GL0_ChartOfAccounts on coa.MainAccount equals c.ControlAccount into cs 
  from ca in cs.DefaultIfEmpty()
  select new 
  {
  	MainAccount = coa.MainAccount, 
	Title = coa.Title, 
	ControlLevel = coa.ControlLevel, 
	ControlAccount = coa.ControlAccount, 
	ControlTitle = ca.Title
	}

Unfortunately, this gives an anonymous type error.

To clarify this, suppose there are three columns:

MainAccount 
Title
ParentAccount

Now I want to get title or name of account instead of ParentAccount(int) how should I write this in LINQ?

Posted 27-Jan-14 23:14pm

Member 7735818

Updated 27-Jan-14 23:47pm

Pete O'Hanlon

v3

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Comments

EduChapow 28-Jan-14 8:55am

You can see somes examples right here:
http://code.msdn.microsoft.com/LINQ-Join-Operators-dabef4e9

2 solutions

Solution 1

var q = (from coa in Glochartofaccount
join c in Glochartofaccount on coamainaccount equals c controlaccount
select new
{
MainAccount = coa.MainAccount,
Title = coa.Title,
ControlLevel = coa.ControlLevel,
ControlAccount = coa.ControlAccount,
ControlTitle = ca.Title
).FirstOrDefault();

Posted 27-Jan-14 23:32pm

NitishBharadwaj

Updated 27-Jan-14 23:33pm

v2

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V5709 · Accepted Answer · 2014-01-29T20:12:00

try by using this sample..

C#

List<employee> emp = new List<employee>();
emp.Add(new Employee()
{
    EmpID = 1,
    EmpName = "a",
    City = "Pune",
    ManagerID = 11
});

emp.Add(new Employee()
{
    EmpID = 2,
    EmpName = "b",
    City = "mumbai",
    ManagerID = 12
});

emp.Add(new Employee()
{
    EmpID = 3,
    EmpName = "c",
    City = "Pune",
    ManagerID = 2
});

emp.Add(new Employee()
{
    EmpID = 4,
    EmpName = "d",
    City = "Delhi",
    ManagerID = 14
});

//----Linq query

var q = (from employee in emp
        join employee2 in emp on employee.EmpID equals employee2.ManagerID
        select employee).FirstOrDefault();
</employee></employee>