根据用户电子邮件选择订阅

Question

我有这些 MySQL 表，我想在其中存储用户订阅：

CREATE TABLE subscription (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `amount` decimal(19,2) DEFAULT NULL,
  `created_at` datetime(6) DEFAULT NULL,
  `currency` varchar(20) DEFAULT NULL,
  `duration` bigint(20) DEFAULT NULL,
  `end_at` datetime(6) DEFAULT NULL,
  `error` varchar(200) DEFAULT NULL,
  `order_id` int(11) DEFAULT NULL,
  `product` varchar(20) DEFAULT NULL,
  `run_at` datetime(6) DEFAULT NULL,
  `start_at` datetime(6) DEFAULT NULL,
  `status` varchar(20) DEFAULT NULL,
  `updated_at` datetime(6) DEFAULT NULL,
  `title` varchar(20) DEFAULT NULL,
  `parent_transaction_id` int(11) DEFAULT NULL,
  `parent_transactionId` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=23443556 DEFAULT CHARSET=latin1;


INSERT INTO subscription (`id`, `amount`, `created_at`, `currency`, `duration`, `end_at`, `error`, `order_id`, `product`, `run_at`, `start_at`, `status`, `updated_at`, `title`, `parent_transaction_id`, `parent_transactionId`) VALUES 
('122', '3333.00', '2020-10-31 19:41:16.622386', 'USD', '1000', '2020-10-31 19:41:16.622386', 'error message', '122', 'error message', '2020-10-31 19:41:16.622386', '2020-10-31 19:41:16.622386', 'active', '2020-10-31 19:41:16.622386', 'title', '443', '5544');

CREATE TABLE `users` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `email` varchar(255) DEFAULT NULL,
  `enabled` tinyint(4) DEFAULT NULL,
  `encrypted_password` varchar(255) DEFAULT NULL,
  `first_name` varchar(255) DEFAULT NULL,
  `last_name` varchar(255) DEFAULT NULL,
  `role` varchar(25) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=153 DEFAULT CHARSET=latin1;

INSERT INTO `users` (`id`, `email`, `enabled`, `encrypted_password`, `first_name`, `last_name`, `role`) VALUES 
('192', 'test@mail.com', '1', '$2a$31$ovShEKleI3Yk2vgjAIF5mO4HkGWXcTSKPMTaj7rFN4KAtlEz0f/ay', 'test', 'test', 'ROLE_CLIENT');

CREATE TABLE `orders` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `city` varchar(30) DEFAULT NULL,
  `CONTENT` text DEFAULT NULL,
  `country` varchar(50) DEFAULT NULL,
  `created_at` datetime(6) DEFAULT NULL,
  `discount` decimal(8,2) DEFAULT NULL,
  `email` varchar(50) DEFAULT NULL,
  `first_name` varchar(50) DEFAULT NULL,
  `grand_total` decimal(8,2) DEFAULT NULL,
  `item_discount` decimal(8,2) DEFAULT NULL,
  `last_name` varchar(50) DEFAULT NULL,
  `line1` varchar(50) DEFAULT NULL,
  `line2` varchar(50) DEFAULT NULL,
  `middle_name` varchar(50) DEFAULT NULL,
  `mobile` varchar(15) DEFAULT NULL,
  `promo` varchar(100) DEFAULT NULL,
  `province` varchar(50) DEFAULT NULL,
  `session_id` int(11) DEFAULT NULL,
  `shipping` decimal(8,2) DEFAULT NULL,
  `status` varchar(100) DEFAULT NULL,
  `sub_total` decimal(8,2) DEFAULT NULL,
  `tax` decimal(8,2) DEFAULT NULL,
  `token` varchar(100) DEFAULT NULL,
  `total` decimal(8,2) DEFAULT NULL,
  `updated_at` datetime(6) DEFAULT NULL,
  `user_id` int(11) DEFAULT NULL,
  `phone` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=65 DEFAULT CHARSET=latin1;

INSERT INTO `orders` (`id`, `city`, `CONTENT`, `country`, `created_at`, `email`, `first_name`, `grand_total`, `item_discount`, `last_name`, `status`, `sub_total`, `tax`, `total`, `user_id`) VALUES 
('122', 'city', 'test context', 'USA', '2021-05-25 12:40:23.793779', 'test@email.com', 'first name', '100', '10', 'last name', 'active', '20', '10', '200', '192');
INSERT INTO `orders` (`id`, `city`, `CONTENT`, `country`, `created_at`, `email`, `first_name`, `grand_total`, `item_discount`, `last_name`, `status`, `sub_total`, `tax`, `total`, `user_id`) VALUES 
('124', 'city', 'test context', 'USA', '2021-05-25 12:40:23.793779', 'test@email.com', 'first name', '100', '10', 'last name', 'active', '20', '10', '200', '192');


CREATE TABLE `order_item` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `discount` decimal(19,2) DEFAULT NULL,
  `order_id` int(11) DEFAULT NULL,
  `price` decimal(19,2) DEFAULT NULL,
  `product_id` int(11) DEFAULT NULL,
  `quantity` int(11) DEFAULT NULL,
  `sku` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

SQLFiddle：http://sqlfiddle.com/#!9/1d6ba6/34

我使用这个带有 2 个 JOINS 的 SQL 查询来获取订阅：

SELECT *
FROM subscription s
INNER JOIN Orders o  ON s.order_id = o.id AND s.id = 122
INNER JOIN users u ON u.id = o.user_id
ORDER BY s.`created_at` 
LIMIT 1; 

如您所见，我使用参数 id 来进行 2 次联接。是否可以仅将用户表中的用户电子邮件作为参数发送并获取找到的订阅记录？

Answer 1

单个表的条件应该放在WHERE 子句中，而不是ON。

SELECT *
FROM subscription s
INNER JOIN Orders o  ON s.order_id = o.id
INNER JOIN users u ON u.id = o.user_id
WHERE u.email = 'user@example.com'
ORDER BY s.`created_at` 
LIMIT 1;