1.MySQL常用命令
1.1 show databases;? 显示现有的数据库
1.2? show tables;? 显示当前数据库所包含的表
1.3? desc dept;? 显示dept表的结构
1.4 select * from dept order by deptno desc limit 3,2;
?dept表先按deptno降序排列，然后取出第三行后面两行的数据
1.5 select now();?取出当前时间
1.6 select date_format(now(),'%d-%m-%y %h:%i:%s);?? 设置当前时间显示的格式

2.连接MySQL数据库

import java.sql.*;

public class TestMysqlConnection {

public static void main(String[] args) {
 Connection conn = null;
 Statement stmt = null;
 ResultSet rs = null;
 try {
  Class.forName("com.mysql.jdbc.Driver");
  conn =  DriverManager.getConnection("jdbc:mysql://localhost/mydata?user=root&password=root");
  stmt = conn.createStatement();
  rs = stmt.executeQuery("select * from dept");
  while (rs.next()) {
   System.out.println(rs.getString("deptno"));
  }
 } catch (ClassNotFoundException e) {
  e.printStackTrace();
 } catch (SQLException ex) {
  System.out.println("SQLException:" + ex.getMessage());
  System.out.println("SQLState:" + ex.getSQLState());
  System.out.println("VendorError:" + ex.getErrorCode());
 }
}
}

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