title: Fail to convert to internal representation JDBC
body: <p>Ok so this is my code</p>
  
  <pre><code>public static ArrayList getMaterialerFraOrdreNr(String s_date, String e_date) throws SQLException, InterruptedException {
      int tal = 0;
  
      ArrayList nameOfColumns = getNameOfColumns();                     // name of columns
      ArrayList orderNumber = getOrdre_Nr_FromDB(s_date, e_date);           // order number 
  
      //første loop kører gennem number of columns
      //anden loop kører gennem name of column
      ResultSet rs = null;
      Connection con = null;
  
      try {
          Class.forName(DB.driver);
          con = DriverManager.getConnection(DB.URL, DB.ID, DB.PW);
  
          for (int i = 1; i &lt; orderNumber.size(); i++) {
              for (int j = 1; j &lt; nameOfColumns.size(); j++) {
  
                  String nameOfColum = (String) nameOfColumns.get(i);
                  int orderNr = (Integer) orderNumber.get(j);
                  System.out.println("orderNr  " + orderNr);
                  //SELECT v1001 FROM ORDRE_spec WHERE  ordre_nr = 1;
                  String query = "SELECT ? AS ans FROM ordre_spec WHERE ordre_nr = ?";
                  PreparedStatement prest = con.prepareStatement(query);
  
                  prest.setString(1, nameOfColum);
                  prest.setInt(2, orderNr);
                  System.out.println("orderNr  "  + orderNr);
                  System.out.println("nameOfColum  =   " + nameOfColum);
                  rs = prest.executeQuery();
                  if(rs.next()){
  
  
                      tal = rs.getInt("ans");
  
                      MaterialeNum.add(tal);
                      System.out.println("materiale num =    " + MaterialeNum);
  
                  }
              }
  
          }
  
      } catch (ClassNotFoundException | SQLException ee) {
          System.out.println("fail og der er så her");
          System.err.println(ee);
      } finally {
  
          con.close();
      }
      System.out.println(kundeNum.toString());
      return kundeNum;
  
  }
  
  public static void main(String[] args) throws SQLException, InterruptedException {
  
      NewClass.getMaterialerFraOrdreNr("1990-10-10", "2020-10-10");
  
  }
  </code></pre>
  
  <p>And my problem is that I'm getting a java.sql.SQLException: Fail to convert to internal representation</p>
  
  <p>I really cant see what the error should be.. plz help if you can see the error :)</p>