Combine three columns into one

SELECT 'Table1'+table1.column+'Table2'+table2.column+'Table3'+table3.column
FROM Table1
    INNER JOIN Table2 on Table1.ID = Table2.id 
    LEFT JOIN/INNER JOIN Table3 on Table2.id = Table3.id // Based on your requirement

SELECT CONCAT(Track_1, ',',Track_2) AS Track, FROM   EMP;
//here is syntax
SELECT SOME_OTHER_COLUMN, CONCAT(FIRSTNAME, ',', LASTNAME) AS FIRSTNAME FROM `customer`;

DataTable dtTrack;   //Say dtTrack contains all the 3 columns Track_1 track_2 Track_3

                foreach (DataRow dr in dtTrack.Rows)
                {
                    DataRow row;
                    row = dtTrack.NewRow();
                    row["Track_1"] = dr["Track_1"].ToString();
                    row["Track_2"] = dr["Track_2"].ToString();
                    row["Track_3"] = dr["Track_3"].ToString();
                    row["Track"] = dr["Track_1"].ToString() + " " + dr["Track_2"].ToString() + " " + dr["Track_3"].ToString();
                    dtTrack.Rows.Add(row);
                }

create table onetable
(
col1 nvarchar(100),
col2 nvarchar(100),
col3 nvarchar(100),
)

insert into onetable values('AA','BB','CC')

select col1 + ' ' + col2 + ' ' + col2 from onetable