如何从mysql中的所有六个表中收集数据答案

【问题标题】：how to gather data from all the six tabels in mysql如何从mysql中的所有六个表中收集数据
【发布时间】：2022-01-28 14:34:44
【问题描述】：

我尝试了内连接，但是我无法弄清楚我在做什么错。怎么查询蓝框内全部6张表的数据。

studentprofile 表是蓝色区域中其他 5 个表之间的链接。

我运行了这个查询，它显示了所有数据。

select * from users, roles_assigned,studentprofile,schoolwithusers;

我面临的问题是我只需要为学生和学校名称和学生个人资料的用户过滤数据请帮忙。这是我的sql代码。

    
--
-- Database: `onlinemarksheets`
--

-- --------------------------------------------------------

--
-- Table structure for table `exams`
--

CREATE TABLE `exams` (
  `id` int(11) NOT NULL,
  `examtye_id` int(11) DEFAULT NULL,
  `schooluser_id` int(11) DEFAULT NULL,
  `duration_to` date DEFAULT NULL,
  `duration_from` date DEFAULT NULL,
  `year` date DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- --------------------------------------------------------

--
-- Table structure for table `examtype`
--

CREATE TABLE `examtype` (
  `id` int(11) NOT NULL,
  `type` enum('Mid-Term','Half-yearly','Yearly') DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `examtype`
--

INSERT INTO `examtype` (`id`, `type`) VALUES
(1, 'Mid-Term'),
(2, 'Half-yearly'),
(3, 'Yearly');

-- --------------------------------------------------------

--
-- Table structure for table `marks`
--

CREATE TABLE `marks` (
  `id` int(11) NOT NULL,
  `exam_id` int(11) DEFAULT NULL,
  `name` varchar(45) DEFAULT NULL,
  `marks_obtained` int(11) DEFAULT NULL,
  `marks_total` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- --------------------------------------------------------

--
-- Table structure for table `roles`
--

CREATE TABLE `roles` (
  `id` int(11) NOT NULL,
  `type` enum('Admin','Teacher','Student') DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `roles`
--

INSERT INTO `roles` (`id`, `type`) VALUES
(1, 'Admin'),
(2, 'Teacher'),
(3, 'Student');

-- --------------------------------------------------------

--
-- Table structure for table `roles_assigned`
--

CREATE TABLE `roles_assigned` (
  `id` int(11) NOT NULL,
  `role_id` int(11) DEFAULT NULL,
  `user_id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `roles_assigned`
--

INSERT INTO `roles_assigned` (`id`, `role_id`, `user_id`) VALUES
(1, 1, 1),
(2, 2, 2),
(3, 3, 3),
(4, 3, 4),
(5, 3, 5),
(6, 3, 6),
(7, 1, 1),
(8, 2, 2),
(9, 3, 3),
(10, 3, 4),
(11, 3, 5),
(12, 3, 6);

-- --------------------------------------------------------

--
-- Table structure for table `schools`
--

CREATE TABLE `schools` (
  `id` int(11) NOT NULL,
  `schoolname` varchar(45) DEFAULT NULL,
  `school_email` varchar(45) DEFAULT NULL,
  `school_phone` varchar(45) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `schools`
--

INSERT INTO `schools` (`id`, `schoolname`, `school_email`, `school_phone`) VALUES
(1, 'D.A.V Public school', 'info@davschool.com', '789456123'),
(2, 'saraswati Public school', 'info@saraswatischool.com', '9998887774'),
(3, 'S.G.R.R Public School', 'Info@sgrr.com', '54245645125'),
(4, 'Sun Valley Public', 'info@sunvalley.com', '23423423424'),
(5, 'Marshal Public school', 'info@marshalschool.com', '23482728347');

-- --------------------------------------------------------

--
-- Table structure for table `schoolwithusers`
--

CREATE TABLE `schoolwithusers` (
  `id` int(11) NOT NULL,
  `school_id` int(11) DEFAULT NULL,
  `studentprofile_id` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `schoolwithusers`
--

INSERT INTO `schoolwithusers` (`id`, `school_id`, `studentprofile_id`) VALUES
(1, 1, 3),
(2, 3, 4);

-- --------------------------------------------------------

--
-- Table structure for table `studentprofile`
--

CREATE TABLE `studentprofile` (
  `id` int(11) NOT NULL,
  `user_id_fk` int(11) DEFAULT NULL,
  `rollno` int(11) DEFAULT NULL,
  `dob` date DEFAULT NULL,
  `attendence` int(11) DEFAULT NULL,
  `class` int(11) DEFAULT NULL,
  `section` enum('A','B') DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `studentprofile`
--

INSERT INTO `studentprofile` (`id`, `user_id_fk`, `rollno`, `dob`, `attendence`, `class`, `section`) VALUES
(1, 3, 22, '2022-01-21', 60, 1, 'A'),
(2, 4, 21, '2012-01-04', 45, 1, 'A'),
(3, 4, 1, '2012-01-04', 100, 3, 'B'),
(4, 5, 30, '2007-04-26', 45, 3, 'B'),
(5, 6, 2, '2022-01-19', 50, 6, 'B');

-- --------------------------------------------------------

--
-- Table structure for table `users`
--

CREATE TABLE `users` (
  `id` int(11) NOT NULL,
  `fname` varchar(45) DEFAULT NULL,
  `lname` varchar(45) DEFAULT NULL,
  `email` varchar(45) DEFAULT NULL,
  `password` varchar(45) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

--
-- Dumping data for table `users`
--

INSERT INTO `users` (`id`, `fname`, `lname`, `email`, `password`) VALUES
(1, 'Shashank', 'Naithani', 'shashank8036@gmail.com', 'lol123'),
(2, 'Kuldeep', 'Negi', 'negikuldeep@gmail.com', 'lop123'),
(3, 'Arpit', 'Thakut', 'Aptha@gmail.com', 'arp123'),
(4, 'Ankit', 'Barthwal', 'ankitbarth@gmail.com', 'ankit123'),
(5, 'Mukesh', 'Thakur', 'sasdb@gmail.com', 'sha123'),
(6, 'Arjun', 'Negi', 'sasdb@gmail.com', 'sha123');

--
-- Indexes for dumped tables
--

--
-- Indexes for table `exams`
--
ALTER TABLE `exams`
  ADD PRIMARY KEY (`id`),
  ADD KEY `examtye_id` (`examtye_id`) USING BTREE,
  ADD KEY `schooluser_id` (`schooluser_id`);

--
-- Indexes for table `examtype`
--
ALTER TABLE `examtype`
  ADD PRIMARY KEY (`id`);

--
-- Indexes for table `marks`
--
ALTER TABLE `marks`
  ADD PRIMARY KEY (`id`),
  ADD KEY `exam_id` (`exam_id`);

--
-- Indexes for table `roles`
--
ALTER TABLE `roles`
  ADD PRIMARY KEY (`id`);

--
-- Indexes for table `roles_assigned`
--
ALTER TABLE `roles_assigned`
  ADD PRIMARY KEY (`id`),
  ADD KEY `role_id` (`role_id`) USING BTREE,
  ADD KEY `user_id` (`user_id`) USING BTREE;

--
-- Indexes for table `schools`
--
ALTER TABLE `schools`
  ADD PRIMARY KEY (`id`);

--
-- Indexes for table `schoolwithusers`
--
ALTER TABLE `schoolwithusers`
  ADD PRIMARY KEY (`id`),
  ADD KEY `school_id` (`school_id`) USING BTREE,
  ADD KEY `studentprofile_id` (`studentprofile_id`);

--
-- Indexes for table `studentprofile`
--
ALTER TABLE `studentprofile`
  ADD PRIMARY KEY (`id`),
  ADD KEY `user_id_idx` (`user_id_fk`);

--
-- Indexes for table `users`
--
ALTER TABLE `users`
  ADD PRIMARY KEY (`id`);

--
-- AUTO_INCREMENT for dumped tables
--

--
-- AUTO_INCREMENT for table `exams`
--
ALTER TABLE `exams`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT;

--
-- AUTO_INCREMENT for table `examtype`
--
ALTER TABLE `examtype`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=4;

--
-- AUTO_INCREMENT for table `marks`
--
ALTER TABLE `marks`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT;

--
-- AUTO_INCREMENT for table `roles`
--
ALTER TABLE `roles`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=4;

--
-- AUTO_INCREMENT for table `roles_assigned`
--
ALTER TABLE `roles_assigned`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=13;

--
-- AUTO_INCREMENT for table `schools`
--
ALTER TABLE `schools`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=6;

--
-- AUTO_INCREMENT for table `schoolwithusers`
--
ALTER TABLE `schoolwithusers`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=3;

--
-- AUTO_INCREMENT for table `studentprofile`
--
ALTER TABLE `studentprofile`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=6;

--
-- AUTO_INCREMENT for table `users`
--
ALTER TABLE `users`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=7;

--
-- Constraints for dumped tables
--

--
-- Constraints for table `exams`
--
ALTER TABLE `exams`
  ADD CONSTRAINT `examtye_id` FOREIGN KEY (`examtye_id`) REFERENCES `examtype` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `schooluser_id` FOREIGN KEY (`schooluser_id`) REFERENCES `schoolwithusers` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;

--
-- Constraints for table `marks`
--
ALTER TABLE `marks`
  ADD CONSTRAINT `exam_id` FOREIGN KEY (`exam_id`) REFERENCES `exams` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;

--
-- Constraints for table `roles_assigned`
--
ALTER TABLE `roles_assigned`
  ADD CONSTRAINT `role_id` FOREIGN KEY (`role_id`) REFERENCES `roles` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `user_id` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;

--
-- Constraints for table `schoolwithusers`
--
ALTER TABLE `schoolwithusers`
  ADD CONSTRAINT `school_id` FOREIGN KEY (`school_id`) REFERENCES `schools` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
  ADD CONSTRAINT `studentprofile_id` FOREIGN KEY (`studentprofile_id`) REFERENCES `studentprofile` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;

--
-- Constraints for table `studentprofile`
--
ALTER TABLE `studentprofile`
  ADD CONSTRAINT `user_id_fk` FOREIGN KEY (`user_id_fk`) REFERENCES `users` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;
COMMIT;

【问题讨论】：

公布你的任务，你做了什么，描述出了什么问题并提供预期的结果
我无法将查询放在一起。我有 2 个映射表 - roles_Assigned - 外键 - roles.id,users.id - schoolwithusers-schools.id,studentprofile.id 现在 studentprofile 表有 user_id 作为外键，我没有办法从这六个中收集数据桌子。请你检查一下桌子的图片。你能检查我的模型设计吗？我做对了吗？我只是一个初学者。到目前为止，我能够查询分配给用户的角色，但不能查询突出显示的蓝色框中的所有 6 个表。请指导我
我运行了这个查询 select * from users, roles_assigned,studentprofile,schoolwithusers;但我不知道该怎么做才能为所有学生的姓名、学校名称、班级作为输出过滤数据

标签： mysql database join

【解决方案1】：

您必须在主键/外键上加入每个表。某些示例数据并不完全正确，因为您在角色分配表中具有重复的 student_id 和 roles_id 值组合。请务必列出您需要的列名，而不是 *。

select * 
from users 
INNER JOIN roles_assigned ON users.id = roles_assigned.user_id 
INNER JOIN roles ON roles.id = roles_assigned.role_id
INNER JOIN studentprofile on studentprofile.id = users.id
INNER JOIN schoolwithusers on schoolwithusers.studentprofile_id = 
    studentprofile.id
INNER JOIN schools ON schools.id = schoolwithusers.school_id
WHERE roles.type = 'Student';

【讨论】：

非常感谢妈妈，这对我有很大帮助。 s 昨天我跑马并创建临时表来获取数据并进行了 3 次查询。您的查询是最好的解决方案。感谢分享知识。