学习MySQL数据库技术是否有助于从事特定行业的工作？

-- 创建用户表
CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(50) NOT NULL,
  `email` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- 创建订单表
CREATE TABLE `orders` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `user_id` int(11) NOT NULL,
  `product` varchar(50) NOT NULL,
  `price` decimal(10,2) NOT NULL,
  `date` date NOT NULL,
  PRIMARY KEY (`id`),
  FOREIGN KEY (`user_id`) REFERENCES `users`(`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- 插入测试数据
INSERT INTO `users` (`username`, `email`, `password`) VALUES
('user1', 'user1@example.com', '123456'),
('user2', 'user2@example.com', '123456');

INSERT INTO `orders` (`user_id`, `product`, `price`, `date`) VALUES
(1, 'product1', 10.00, '2022-01-01'),
(2, 'product2', 20.00, '2022-01-02');

-- 查询用户的订单
SELECT `users`.`username`, `orders`.`product`, `orders`.`price`, `orders`.`date` 
FROM `users` 
JOIN `orders` ON `users`.`id` = `orders`.`user_id` 
WHERE `users`.`username` = 'user1';

-- 统计每个用户的订单总额
SELECT `users`.`username`, SUM(`orders`.`price`) AS `total_price`
FROM `users`
JOIN `orders` ON `users`.`id` = `orders`.`user_id`
GROUP BY `users`.`username`;