How to get column values in one comma separated value

Question

I have a table which contains rows like below

ID  User      Department
1   User1     Admin
2   User1     Accounts
3   User2     Finance
4   User3     Sales
5   User3     Finance

I need a select query which results following format

ID  User      Department
1   User1     Admin,Accounts
2   User2     Finance
3   User3     Sales, Finance

Answer 1

You tagged the question with both sql-server and plsql so I will provide answers for both SQL Server and Oracle.

In SQL Server you can use FOR XML PATH to concatenate multiple rows together:

select distinct t.[user],
  STUFF((SELECT distinct ', ' + t1.department
         from yourtable t1
         where t.[user] = t1.[user]
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,2,'') department
from yourtable t;

See SQL Fiddle with Demo.

In Oracle 11g+ you can use LISTAGG:

select "User",
  listagg(department, ',') within group (order by "User") as departments
from yourtable
group by "User"

See SQL Fiddle with Demo

Prior to Oracle 11g, you could use the wm_concat function:

select "User",
  wm_concat(department) departments
from yourtable
group by "User"

Answer 2

In Sql Server you can use it.

DECLARE @UserMaster TABLE( 

    UserID INT NOT NULL, 

    UserName varchar(30) NOT NULL 

); 

INSERT INTO @UserMaster VALUES (1,'Rakesh')

INSERT INTO @UserMaster VALUES (2,'Ashish')

INSERT INTO @UserMaster VALUES (3,'Sagar')

SELECT * FROM @UserMaster

DECLARE @CSV VARCHAR(MAX) 

SELECT @CSV = COALESCE(@CSV + ', ', '') + UserName from @UserMaster 

SELECT @CSV AS Result