How to append data in resultset?

Question

I want to append data of two tables in a resultset. I have tried the below code but not getting the desired output only the first resultset data ie the first table data

   ResultSet rs=null;
            String sql_query="select * from exception_main;select * from m_roles"
            String query1=sql_query.toUpperCase();
                        String[] results=query1.split(";");
                for(int i=0;i<results.length;i++)
                    {
                        if(results[i].startsWith("SELECT"))
                        {
                            System.out.println("Inside select"+ results[i]);
                        ps = conn1.prepareStatement(results[i].toString());
                        rs = ps.executeQuery();

    ...
                   //writing to csv file
                    CSVWriter writer = new CSVWriter(new FileWriter(csv_file_path + csv_file_name), ',',CSVWriter.NO_QUOTE_CHARACTER);
                    System.out.println("Count..." + rs.getRow());
                    writer.writeAll(rs, true);
                    System.out.println("Count...2::::" + rs.getRow());
                    writer.close();
                     while(rs.next()){

                            rs.deleteRow();

                          }
                     System.out.println("Count...3:::::::" + rs1.getRow());
}
}

I am getting Count as 0 in all three places Guide me please.

Answer 1

You should pull all the data from each ResultSet before executing a new query using the same connection.

Under the covers, the ResultSet object is making using of the connection/statement in order to pull data from the db. When you execute a new query using that connection, the existing query info will be trashed.

Hence you should iterate through each ResultSet and pull the data (into a custom object, most likely) before executing the next query.

Answer 2

opened the file before the for loop and closed it afterwards, rather than opening and closing it every time round the loop.

ResultSet rs=null;
                String sql_query="select * from exception_main;select * from m_roles"
                String query1=sql_query.toUpperCase();
                            String[] results=query1.split(";");
        CSVWriter writer = new CSVWriter(new FileWriter(csv_file_path + csv_file_name), ',',CSVWriter.NO_QUOTE_CHARACTER);
                    for(int i=0;i<results.length;i++)
                        {
                            if(results[i].startsWith("SELECT"))
                            {
                                System.out.println("Inside select"+ results[i]);
                            ps = conn1.prepareStatement(results[i].toString());
                            rs = ps.executeQuery();




        ...
                       //writing to csv file

                        System.out.println("Count..." + rs.getRow());
                        writer.writeAll(rs, true);
                        System.out.println("Count...2::::" + rs.getRow());
                                             while(rs.next()){

                                rs.deleteRow();

                              }
                         System.out.println("Count...3:::::::" + rs1.getRow());
    }
    }
    writer.close();