How to Use executeQuery() in Java for Database Queries

1
2// !!!   import this    !!!
3import java.sql.PreparedStatement;
4import java.sql.ResultSet;
5import java.sql.Connection
6
7// in your CLASS
8// initialize variable 
9// myRS with type ResultSet 
10// myPStmt with type PreparedStatement
11// myConn with type Connection
12
13public class ExampleExequteQeury {
14
15   public static PreparedStatement myPStmt = null;
16   public static ResultSet myRs = null;
17   public static Connection myConn = null;
18
19   // create a METHOD
20   // In here I'm using NetBeans
21   // this method works when you click the button
22   // the action will execute the query
23
24   private void btnAvgActionPerformed(java.awt.event.ActionEvent evt){
25
26      try {
27
28         // sample query
29         //             "SELECT AVG(<field>) from <table name>" 
30
31         String query = "SELECT AVG(finalamount) from tblentry";
32
33         // Prepare Statement 
34
35         myPStmt = myConn.prepareStatement(query);
36
37         // Execute SQL query and get the result
38
39         myRs = myPStmt.executeQuery();
40
41         if (myRs.next()) {
42
43            String averageAmount = myRs.getString(1);
44            System.out.println(averageAmount);
45
46         } else {
47
48            System.out.println("No Data Found");
49            
50         }
51
52      } catch(SQLException e) {
53
54         JOptionPane.showMessageDialog(null, "SQL Error: " + e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);            
55      }    
56
57   }
58
59}
60