CODEWITHSUNDEEP
javamysqlsqlarraysoracle-database
John Joe
John Joe

Reputation: 12803

How to retrieve values from SQL when ID is in array form

The function below will pick the highest value and it will display value which are in column place1(in table placeseen) as output based on the ID.So far I only can get the highest value but not the value in place1. I don't know what's wrong with my coding because the output is always shows empty. 

   private void pick_highest_value_here_and_display(ArrayList<Double> value) throws Exception {
            // TODO Auto-generated method stub
            double aa[]=value.stream().mapToDouble(v -> v.doubleValue()).toArray();
            double highest=aa[0+1];
            for(int i=0;i<aa.length;i++)
            {
                if(aa[i]>highest){
                    highest=aa[i];
                    String sql ="Select* from placeseen where ID =aa[i]";
                    DatabaseConnection db = new DatabaseConnection();
                    Connection  conn =db.getConnection();
                    PreparedStatement  ps = conn.prepareStatement(sql);
                    ResultSet rs = ps.executeQuery();
                    if (rs.next()) 
                    {  
                    String aaa;
                    aaa=rs.getString("place1");
                    System.out.println(aaa);
                    }
                    ps.close();
                    rs.close();
                    conn.close();
                }

            }

            System.out.println(highest);
        }

Upvotes: 1

Views: 210

Answers (2)

SatyaTNV
SatyaTNV

Reputation: 4135

instead of

  String sql ="Select * from placeseen where ID =aa[i]";//aa[i] taking a value

use 

  String sql ="Select place1 from placeseen where ID =?";
  PreparedStatement ps = conn.prepareStatement(sql);
  ps.setDouble(1, aa[i]);

passing aa[i] variable value .

Avoid sql injection

Upvotes: 1

Naman Gala
Naman Gala

Reputation: 4692

You can try this

// as you are using preparedStatement you can use ? and then set value for it to prevent sql injection
String sql = "Select * from placeseen where ID = ?";
DatabaseConnection db = new DatabaseConnection();
Connection conn = db.getConnection();
PreparedStatement ps = conn.prepareStatement(sql);
ps.setDouble(1, aa[i]);  // 1 represent first attribute represented by ?

System.out.println(ps); // this will print query in console

ResultSet rs = ps.executeQuery();
if (rs.next()) {
    System.out.println("Inside rs.next()");  // for debug purpose
    String aaa;
    aaa=rs.getString("place1");
    System.out.println(aaa);
}
// remaining code

Upvotes: 0

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