如何使用sql连接mysql数据库服务器

 id INT PRIMARY KEY,

 name VARCHAR(50),

 age INT

 ```python

 import pymysql

 # 建立连接

 connection = pymysql.connect(

     host='localhost',

     user='username',

     password='password',

     database='mydatabase'

 )

 # 执行SQL查询

 with connection.cursor() as cursor:

     sql = "SELECT * FROM mytable"

     cursor.execute(sql)

     result = cursor.fetchall()

     for row in result:

         print(row)

 # 关闭连接

 connection.close()

 ```

 ```java

 import java.sql.*;

 public class Main {

     public static void main(String[] args) {

         try {

             // 加载驱动

             Class.forName("com.mysql.jdbc.Driver");

             // 建立连接

             Connection connection = DriverManager.getConnection(

                 "jdbc:mysql://localhost/mydatabase",

                 "username",

                 "password"

             );

             // 创建Statement对象

             Statement statement = connection.createStatement();

             // 执行SQL查询

             String sql = "SELECT * FROM mytable";

             ResultSet resultSet = statement.executeQuery(sql);

             while (resultSet.next()) {

                 int id = resultSet.getInt("id");

                 String name = resultSet.getString("name");

                 int age = resultSet.getInt("age");

                 System.out.println(id + ", " + name + ", " + age);

             }

             // 关闭连接

             resultSet.close();

             statement.close();

             connection.close();

         } catch (Exception e) {

             e.printStackTrace();

         }

     }

 }

 ```