Schema
CREATE TABLE IF NOT EXISTS `exams` (
`id` int(6) unsigned NOT NULL,
`name` varchar(100) NOT NULL,
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `institutions` (
`id` int(6) unsigned NOT NULL,
`name` varchar(100) NOT NULL,
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
CREATE TABLE IF NOT EXISTS `exam_scores` (
`id` int(6) unsigned NOT NULL,
`exam_id` int(6) NOT NULL,
`institution_id` int(6) NOT NULL,
`score` int(5)
PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;
INSERT INTO `exams` (`id`, `name`) VALUES
('1', 'exam1'),
('2', 'exam2'),
('3', 'exam3'),
('4', 'exam4');
('5', 'exam5');
INSERT INTO `institutions` (`id`, `name`) VALUES
('1', 'institution1'),
('2', 'institution2'),
('3', 'institution3'),
('4', 'institution4');
('5', 'institution5');
INSERT INTO `exam_scores` (`id`, `exam_id`, `institution_id`, `score`) VALUES
('1', '1', 1, 40),
('2', '2', 1, 45),
('3', '3', 2, 35),
('4', '1', 2, 30);
('5', '4', 3, 40);
Now the user will input exm1
I am trying to create a query to find all related exams like below.
Find exams matching input exm1
and also find other exams existing in matched institutions inn exam_scores
table.
Example 1: input exm4
desired output
| exm4 |
Example 2: input exm3
desired ouput
| exm3 |
| exm1 |
Example 3: input exm1
desired output
| exm1 |
| exm2 |
| exm3 |
So far I have only come up with a query which gives only matched exam :)
select exams.name from exams
inner join exam_scores on exam_scores.exam_id = exams.id
// ??
where exams.id = 1
You can do this with join
s:
select distinct e1.name
from exams e1
inner join exam_scores es1 on es1.exam_id = e1.id
inner join exam_scores es2 on es2.institution_id = es1.institution_id
inner join exams e2 on e2.id = es2.exam_id
where e2.name = ?