Returning comma seperated details from a table ...

I saw an question in one of the SQL newsgroup which I visit frequently (offlate). That person is having a problem with retriving data from a table. Let me explain it in detail.

Sample table structure:

Create table empTest
(
[Id] int identity,
Contact varchar(100),
Employee_Id int
)
Go

Let us populate few records into the table:

Insert into empTest (Contact, Employee_Id) values ( 'vmvadivel@gmail.com', 101)
Insert into empTest (Contact, Employee_Id) values ( '04452014353', 101)
Insert into empTest (Contact, Employee_Id) values ( 'vmvadivel@yahoo.com', 102)
Insert into empTest (Contact, Employee_Id) values ( '9104452015000', 102)
Go

And now, as you could see each employee has more than one contact details. So if you query the table as Select * from EmpTest it would list couple of records for each employee. Instead of this won't it be nice if we could generate comma seperated contact details for each employee. i.e., There would be only one record for an employee.

Something like this, (Employee_Id, Contact )

101 vmvadivel@gmail.com, 04452014353
102 vmvadivel@yahoo.com, 9104452015000
etc.,

Solution:

-- Temp variable
Declare @strContact varchar(8000)

-- Build the comma seperated contact list
Select @strContact = Coalesce(@strContact + ', ', '') + ET.Contact From empTest ET where ET.Employee_Id = 101

--Display the comma seperated contact list
Select @strContact

This above code snippet would work for a given employee id. Now this can generalized to work for all employee id as shown below:

Create function dbo.GetEmpDetails(@EmpID int)
Returns Varchar(8000)
As
Begin
Declare @Contact varchar(8000)
Select @Contact = Coalesce(@Contact + ', ', '') + ET.Contact From empTest ET
Where ET.Employee_Id = @EmpID

Return @Contact
End
Go

Select distinct Employee_ID, dbo.GetEmpDetails(Employee_Id) as ListOfContacts From empTest
Go

To be frank I got the base logic from an article in 4guysfromrolla.com and customized it according to our need here.