千峰逆战班，Day41，MySQL作业

数据库作业：

1.1 查询所有用户的订单

SELECT username,address,phone,oid,totalprice
FROM USER
INNER JOIN orders
ON user.`userId`=orders.`userId`;

查询结果：

1.2 查询用户id为 1 的所有订单详情

SELECT username,address,phone,orderitem.oid,cname,NAME,price,num,totalprice
FROM USER
INNER JOIN orders
ON user.`userId`=orders.`userId`
INNER JOIN orderitem
ON orders.`oid`=orderitem.`oid`
INNER JOIN products
ON orderitem.`pid`=products.`pid`
INNER JOIN category
ON products.`category_id`=category.`cid`
WHERE user.`userId`=1;

2.1查看用户为张三的订单

SELECT orders.`oid`,totalprice
FROM orders 
WHERE userid =(SELECT userid FROM USER WHERE username='张三');

查询结果：

2.2查询出订单的价格大于800的所有用户信息

SELECT username,PASSWORD,address,phone
FROM USER
WHERE userid IN (SELECT userid FROM orders WHERE totalprice>800);

查询结果：

3.1查询所有订单信息，每页显示5条数据

SELECT username,address,phone,oid,totalprice
FROM USER 
INNER JOIN orders
ON user.`userId`=orders.`userId`
LIMIT 0,5;

查询结果：

JDBC核心六步（增删改）

public class TestJDBC {
    public static void main(String[] args) throws Exception{
        /**
         * 用户表
         */
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/hy3_28?useUnicode=true&characterEncoding=utf8";
        String user = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url,user,password);
        Statement statement = connection.createStatement();
        System.out.println("进行新增操作");
        String sql = "insert into user(username,password,address,phone)values('侯5',12345,'山西','13000001111')";
        int insResult = statement.executeUpdate(sql);
        dispose(insResult);

        System.out.println("进行修改操作");
        String sql1 = "update user set username='侯哈哈' where userid = 1";
        int updResult = statement.executeUpdate(sql1);
        dispose(updResult);

        System.out.println("进行删除操作");
        String sql2 = "delete from user where userid = 5";
        int delResult = statement.executeUpdate(sql2);
        dispose(delResult);
        
        statement.close();
        connection.close();
    }
    public static void dispose(int result){
        if(result > 0){
            System.out.println("修改成功");
        }else{
            System.out.println("修改失败");
        }
    }
}

public class TestJDBC {
    public static void main(String[] args) throws Exception{
        /**
         * 分类表
         */
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/hy3_28?useUnicode=true&characterEncoding=utf8";
        String user = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url,user,password);
        Statement statement = connection.createStatement();
        System.out.println("进行新增操作");
        String sql = "insert into category(cid,cname)values('c006','零食')";
        int insResult = statement.executeUpdate(sql);
        dispose(insResult);

        System.out.println("进行修改操作");
        String sql1 = "update category set cname='食品' where cid='coo4'";
        int updResult = statement.executeUpdate(sql1);
        dispose(updResult);

        System.out.println("进行删除操作");
        String sql2 = "delete from category where cid='c005'";
        int delResult = statement.executeUpdate(sql2);
        dispose(delResult);

        statement.close();
        connection.close();
    }
    public static void dispose(int result){
        if(result > 0){
            System.out.println("修改成功");
        }else{
            System.out.println("修改失败");
        }
    }
}

public class TestJDBC {
    public static void main(String[] args) throws Exception{
        /**
         * 商品表
         */
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/hy3_28?useUnicode=true&characterEncoding=utf8";
        String user = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url,user,password);
        Statement statement = connection.createStatement();
        System.out.println("进行新增操作");
        String sql = "insert into products(pid,NAME,price,category_id) VALUES('p012','香蕉',3000,'c007')";
        int insResult = statement.executeUpdate(sql);
        dispose(insResult);

        System.out.println("进行修改操作");
        String sql1 = "update products set name='耐克' where pid='p007'";
        int updResult = statement.executeUpdate(sql1);
        dispose(updResult);

        System.out.println("进行删除操作");
        String sql2 = "delete from products where pid='p010'";
        int delResult = statement.executeUpdate(sql2);
        dispose(delResult);

        statement.close();
        connection.close();
    }
    public static void dispose(int result){
        if(result > 0){
            System.out.println("修改成功");
        }else{
            System.out.println("修改失败");
        }
    }
}

public class TestJDBC {
    public static void main(String[] args) throws Exception{
        /**
         * 订单表
         */
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/hy3_28?useUnicode=true&characterEncoding=utf8";
        String user = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url,user,password);
        Statement statement = connection.createStatement();
        System.out.println("进行新增操作");
        String sql = "insert into orders(oid,totalprice,userid) VALUES('o6104',3000.20,4)";
        int insResult = statement.executeUpdate(sql);
        dispose(insResult);

        System.out.println("进行修改操作");
        String sql1 = "update orders set userid = 3 where oid='o6101'";
        int updResult = statement.executeUpdate(sql1);
        dispose(updResult);

        System.out.println("进行删除操作");
        String sql2 = "delete from orders where oid='o6103'";
        int delResult = statement.executeUpdate(sql2);
        dispose(delResult);

        statement.close();
        connection.close();
    }
    public static void dispose(int result){
        if(result > 0){
            System.out.println("修改成功");
        }else{
            System.out.println("修改失败");
        }
    }
}

public class TestJDBC {
    public static void main(String[] args) throws Exception{
        /**
         * 订单详表
         */
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/hy3_28?useUnicode=true&characterEncoding=utf8";
        String user = "root";
        String password = "1234";
        Connection connection = DriverManager.getConnection(url,user,password);
        Statement statement = connection.createStatement();
        System.out.println("进行新增操作");
        String sql = "insert into orderitem(oid,pid,num) VALUES('o6104','p007',2)";
        int insResult = statement.executeUpdate(sql);
        dispose(insResult);

        System.out.println("进行修改操作");
        String sql1 = "update orderitem set oid ='o6104' where pid='p002'";
        int updResult = statement.executeUpdate(sql1);
        dispose(updResult);

        System.out.println("进行删除操作");
        String sql2 = "delete from orderitem where pid='p003'";
        int delResult = statement.executeUpdate(sql2);
        dispose(delResult);

        statement.close();
        connection.close();
    }
    public static void dispose(int result){
        if(result > 0){
            System.out.println("修改成功");
        }else{
            System.out.println("修改失败");
        }
    }
}