Datatable: System.Byte[] value in datatable result

Question

the result for value1 is giving error. col2 's datatype is int. col1 's datatype is string. even though i bring the string value or int value in if condition it accepts int value only.

        string str = "SELECT col1,"
                             + "if(col2=0,col1,col2) col2,"
                             + "col3"
                             + "FROM table1"
                             + "ORDER BY col1 ASC";
        connection.Open();
        cmd = new MySqlCommand(strdept_name, connection);
        adapter = new MySqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        adapter.Fill(dt);
        connection.Close();
        cmd.Parameters.Clear();


        string value1 = dt.Rows[i].Field<string>("col2").ToString();

Please help me understand what is wrong here?

Answer 1

You can change col2 to string with concat('',col2) or convert col1 to int, choose one.

 string str = "SELECT col1,"
                         + "if(col2=0,col1,concat('',col2)) col2,"
                         + "col3"
                         + "FROM table1"
                         + "ORDER BY col1 ASC";
    connection.Open();
    cmd = new MySqlCommand(strdept_name, connection);
    adapter = new MySqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    adapter.Fill(dt);
    connection.Close();
    cmd.Parameters.Clear();


    string value1 = dt.Rows[i]["col2"].ToString();