为什么我的 MySql-Query 不能按照我希望的方式工作？

Question

我有一个 MySQL-DB，它有三个表：药物、成分（两者都有 m:n 关系）和一个链接表/关联表。所以很明显一种药物可以有多种成分，并且成分可以存在于多种药物中。我想创建一个网站，我的用户可以在其中选择

DROP procedure IF EXISTS `getMeds`;

DELIMITER $$
USE `epharmacy`$$
CREATE PROCEDURE `getMeds` (IN all1 VARCHAR(10), IN all2 VARCHAR(10), IN all3 VARCHAR(10), 
                            IN unall1 VARCHAR(10), IN unall2 VARCHAR(10), IN unall3 VARCHAR(10))
BEGIN
SELECT m_id, m_name, i_id, i_name FROM epharmacy.`mi_med-ing` INNER JOIN epharmacy.`m_medication` 
INNER JOIN epharmacy.`i_ingredients` 
ON mi_m_id = m_id AND mi_i_id = i_id

#Allowed
WHERE (i_id = all1 OR all1 = '') 
AND (i_id = all2 OR all2 = '')
AND (i_id = all3 OR all3 = '') 

#Unallowed
AND ((i_id!= unall1 OR unall1 = '') 
AND (i_id != unall2 OR unall2 = '') 
AND (i_id != unall3 OR unall3 = ''))

ORDER BY m_id ASC;
END
$$
DELIMITER ;

call getMeds('I005', 'I006', 'I007', 'I001', 'I002', 'I003');

但这不知何故不起作用。我应该得到两种药物作为回报，但我什么也没得到。我尝试了很多东西，比如子查询和其他 JOINS，但没有帮助。希望你能:)

编辑： 这就是我的数据库的样子： m_medication：

CREATE TABLE IF NOT EXISTS `m_medication` (
  `m_id` varchar(10) NOT NULL,
  `m_name` varchar(500) DEFAULT NULL,
  PRIMARY KEY (`m_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `m_medication` (`m_id`, `m_name`) VALUES('M00001', 'drug1');
INSERT INTO `m_medication` (`m_id`, `m_name`) VALUES('M00002', 'drug2');

i_ingredients：

CREATE TABLE IF NOT EXISTS `i_ingredients` (
  `i_id` varchar(10) NOT NULL,
  `i_name` varchar(500) DEFAULT NULL,
  PRIMARY KEY (`i_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `i_ingredients` (`i_id`, `i_name`) VALUES('I005', 'ingredient1');
INSERT INTO `i_ingredients` (`i_id`, `i_name`) VALUES('I006', 'ingredient2');
INSERT INTO `i_ingredients` (`i_id`, `i_name`) VALUES('I007', 'ingredient3');

mi_med-ing：

CREATE TABLE IF NOT EXISTS `mi_med-ing` (
  `mi_id` varchar(10) NOT NULL,
  `mi_i_id` varchar(10) DEFAULT NULL,
  `mi_m_id` varchar(10) DEFAULT NULL,
  PRIMARY KEY (`mi_id`),
  KEY `mi_i_id` (`mi_i_id`),
  KEY `mi_m_id` (`mi_m_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO mi_med-ing (mi_id, mi_i_id, mi_m_id) VALUES('MI001', 'I005', 'M00001'); 
INSERT INTO mi_med-ing (mi_id, mi_i_id, mi_m_id) VALUES('MI002', 'I006', 'M00001'); 
INSERT INTO mi_med-ing (mi_id, mi_i_id, mi_m_id) VALUES('MI003', 'I007', 'M00001'); 
INSERT INTO mi_med-ing (mi_id, mi_i_id, mi_m_id) VALUES('MI004', 'I005', 'M00002'); 
INSERT INTO mi_med-ing (mi_id, mi_i_id, mi_m_id) VALUES('MI005', 'I006', 'M00002'); 
INSERT INTO mi_med-ing (mi_id, mi_i_id, mi_m_id) VALUES('MI006', 'I007', 'M00002');

外键：

ALTER TABLE `mi_med-ing`
  ADD CONSTRAINT `mi_med-ing_ibfk_1` FOREIGN KEY (`mi_i_id`) REFERENCES `i_ingredients` (`i_id`),
  ADD CONSTRAINT `mi_med-ing_ibfk_2` FOREIGN KEY (`mi_m_id`) REFERENCES `m_medication` (`m_id`);

Answer 1

一共有三个表：

• m_medication = 药物
• i_ingredients = 成分
• mi_med-ing = m:n 关系的桥接表

您想退回药品及其所有成分，以下适用于药品：

• 所有需要的成分都在药物中
• 药物中没有不良成分

两步：

1. 汇总每种药物的桥接表以查找满足所有要求的所有药物。
2. 选择所有由此找到的药物及其成分。

程序：

CREATE PROCEDURE getMeds (IN all1 VARCHAR(10), IN all2 VARCHAR(10), IN all3 VARCHAR(10), 
                          IN unall1 VARCHAR(10), IN unall2 VARCHAR(10), IN unall3 VARCHAR(10))
BEGIN
  SELECT m.*, i.*
  FROM epharmacy.m_medication m
  JOIN epharmacy.`mi_med-ing` mi ON mi.mi_m_id = m.m_id
  JOIN epharmacy.i_ingredients i ON i.i_id = mi.mi_i_id
  WHERE m.m_id IN
  (
    SELECT mi_m_id
    FROM epharmacy.`mi_med-ing`
    GROUP BY mi_m_id
    HAVING (all1   = '' OR SUM(mi_i_id = all1)   > 0)
       AND (all2   = '' OR SUM(mi_i_id = all2)   > 0)
       AND (all3   = '' OR SUM(mi_i_id = all3)   > 0)
       AND (unall1 = '' OR SUM(mi_i_id = unall1) = 0)
       AND (unall2 = '' OR SUM(mi_i_id = unall2) = 0)
       AND (unall3 = '' OR SUM(mi_i_id = unall3) = 0)
  )
  ORDER BY m.m_id, i.i_id;
END

聚合的工作原理：在 MySQL 中，true = 1 和 false = 0。我将布尔表达式相加，因此当根本没有匹配时得到 0，或者当组中有匹配时得到 > 0。

演示：https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=2e623f39daac369e3ac58ff1b18d992b

Answer 2

要查找具有所有所需成分的所有药物，您需要在连接表中执行分组查询；见How to return rows that have the same column values in MySql。

要排除不允许的成分，请使用返回包含这些成分的任何药物的子查询，然后使用m_id NOT IN (subquery) 将它们过滤掉。

CREATE PROCEDURE `getMeds` (IN all1 VARCHAR(10), IN all2 VARCHAR(10), IN all3 VARCHAR(10), 
                            IN unall1 VARCHAR(10), IN unall2 VARCHAR(10), IN unall3 VARCHAR(10))
BEGIN
DECLARE all_count INT DEFAULT (all1 != '') + (all2 != '') + (all3 != '');
SELECT m_id, m_name, i_id, i_name
FROM (SELECT mi_m_id
      FROM `mi_med-ing`
      WHERE mi_i_id IN (all1, all2, all3)
      GROUP BY mi_m_id
      HAVING COUNT(*) = all_count) AS a
INNER JOIN `mi_med-ing` AS mi ON mi.mi_m_id = a.mi_m_id
INNER JOIN `m_medication` ON mi.mi_m_id = m_id
INNER JOIN `i_ingredients` ON mi.mi_i_id = i_id
WHERE m_id NOT IN (
    SELECT mi_m_id
    FROM `mi_med-ing`
    WHERE mi_i_id IN (unall1, unall2, unall3)
)
ORDER BY m_id ASC;
END