mysql

1、 create database 库名 create table 表名()
2、select 2+4..可以计算和
3、insert into tablename values('','')
4、分页: select * from tablename desc limit 3,3， 从第3个往后的3个元素
5、datetime ： select now()
6、表结构：desc tablename
7、mysql数据库连接jdbc
a. 准备工作
IntelliJ IDEA
mysql ——products ——mysql-connector-java-5.0.8-bin（不是最新版本）
建立数据库 customer
建表 customer
b.定义数据库信息

//数据库地址
    private static final String url = "jdbc:mysql://localhost:3306/customer";
    private static final String name = "com.mysql.jdbc.Driver";
    private static final String username = "这里填上你的数据库名称";
    private static final String password = "这里填上你的数据库的密码";
    private Connection connection = null;  
    private PreparedStatement  preparedStatement =null;

c.开启连接

private DBManager(String sql){
        try{
            Class.forName(name);
            connection = DriverManager.getConnection(url, username, password);
            preparedStatement = connection.prepareStatement(sql);

        }catch(Exception e){
            e.printStackTrace();
        }
    }

d.进行操作后需要的关闭连接

private void close(){
        try{
            this.connection.close();
            this.preparedStatement.close();
        }catch (Exception e){
            e.printStackTrace();
        }
    }

e. 写个demo

public static void main(String[] args){
        String sql = "SELECT * FROM customer";
        DBManager dbManager = new DBManager(sql);  //实例化

        String id, name, gender, phone, email, description;

        try{
            ResultSet result = dbManager.preparedStatement.executeQuery();
            while(result.next()){                  //若有数据，就输出
                id = result.getString(1);
                name = result.getString(2);
                gender = result.getString(3);
                phone = result.getString(4);
                email = result.getString(5);
                description = result.getString(6);
                //显示出每一行数据
                System.out.println(id + "  " + name + "  " + gender + "  "
                                    + phone + "  " + email + "  " + description);
            }
            result.close();
            dbManager.close();
            
        }catch (Exception e){
            e.printStackTrace();
        }
    }
···