INSERT INTO `user` (username, password, chinesename)
VALUES ('john_doe', '2022024583', 'yujifeng'),
('jane_smith', 'securepass', 'yu');
-- 查询所有用户(查询)
SELECT * FROM `user`;
-- 根据用户名查询用户(查询)
SELECT * FROM `user` WHERE username = 'john_doe';
-- 更新用户信息(修改)
UPDATE `user`
SET password = 'new_secure_password', chinesename = '于纪丰'
WHERE username = 'john_doe';
-- 删除用户(删除)
DELETE FROM `user` WHERE username = 'jane_smith';