How to Loop and Update SQL Table Summing any existing Values

    DataTable dt = GetDatafromDatabase(); //===== returns a DataTable

    string SQLT = "SELECT * FROM tbl_TempReport";

    string colname;

    if (cn.State == ConnectionState.Closed)

    {

     cn.Open();

    }

    SqlCommand cmdT = new SqlCommand(SQLT, cn);

    SqlDataReader rt = cmdT.ExecuteReader();

    while (rt.Read())

    {

// For each row, print the values of each column.

    foreach (DataColumn column in dt.Columns)

    {

    foreach (DataRow row in dt.Rows)

    {

    colname = column.ColumnName.ToString();

    int mValue = 0;

    string m_Code = rt["code"].ToString();

    if (m_Code == colname)

    {

     if (m_Code == colname && mValue > 0) { mValue +=        Convert.ToInt32(row[column].ToString()); } else { mValue =     Convert.ToInt32(row[column].ToString()); }

//============ insert into tbl_TempReport to match the appropriate column

    string SQLP = "UPDATE tbl_TempReport SET VALUEP = @VALUEP WHERE code =     @code";

    SqlCommand cmdp = new SqlCommand(SQLP, cn);

    cmdp.Parameters.AddWithValue("@VALUEP", SqlDbType.Int).Value = mValue;

    cmdp.Parameters.AddWithValue("@code", SqlDbType.NVarChar).Value = rt["code"].ToString();

    cmdp.ExecuteNonQuery();

    }

    }

    }

    }