Concatenate Column Values of a table using COALESCE

DECLARE @ColumnNameList VARCHAR (MAX)

 SELECT   @ColumnNameList   = COALESCE (@ColumnNameList +',' , '') + Column Name

                                                             FROM

                                                               <<Table Name>>

SELECT @ColumnNameList

Eg:

Create table Emp(empid int, ename varchar(100))

Insert into Emp values(1,'Ganga');

Insert into Emp values(1,'Raju');

Insert into Emp values(1,'Kondapalli');

DECLARE @ColumnNameList VARCHAR (MAX)

 SELECT   @ColumnNameList   = COALESCE (@ColumnNameList +',' , '') + ename

                                                                                 FROM

                                                                                   Emp

SELECT @ColumnNameList

Result:

Ganga,Raju,Kondapalli