how to write queries in java

1import java.sql.*;
2
3/**
4 * A Java MySQL SELECT statement example.
5 * Demonstrates the use of a SQL SELECT statement against a
6 * MySQL database, called from a Java program.
7 * 
8 * Created by Alvin Alexander, http://alvinalexander.com
9 */
10public class JavaMysqlSelectExample
11{
12
13  public static void main(String[] args)
14  {
15    try
16    {
17      // create our mysql database connection
18      String myDriver = "org.gjt.mm.mysql.Driver";
19      String myUrl = "jdbc:mysql://localhost/test";
20      Class.forName(myDriver);
21      Connection conn = DriverManager.getConnection(myUrl, "root", "");
22      
23      // our SQL SELECT query. 
24      // if you only need a few columns, specify them by name instead of using "*"
25      String query = "SELECT * FROM users";
26
27      // create the java statement
28      Statement st = conn.createStatement();
29      
30      // execute the query, and get a java resultset
31      ResultSet rs = st.executeQuery(query);
32      
33      // iterate through the java resultset
34      while (rs.next())
35      {
36        int id = rs.getInt("id");
37        String firstName = rs.getString("first_name");
38        String lastName = rs.getString("last_name");
39        Date dateCreated = rs.getDate("date_created");
40        boolean isAdmin = rs.getBoolean("is_admin");
41        int numPoints = rs.getInt("num_points");
42        
43        // print the results
44        System.out.format("%s, %s, %s, %s, %s, %s\n", id, firstName, lastName, dateCreated, isAdmin, numPoints);
45      }
46      st.close();
47    }
48    catch (Exception e)
49    {
50      System.err.println("Got an exception! ");
51      System.err.println(e.getMessage());
52    }
53  }
54}
55

12, Fred, Flinstone, 2010-06-23, false, 6000
23, Barney, Rubble, 2010-06-23, false, 5000
3