How to use MySQL to create the examination results query table structure of the online examination system?

How to use MySQL to create the examination results query table structure of the online examination system?

Online examination system is an increasingly popular educational tool that can conveniently provide students with examination opportunities and provide fast and accurate feedback on examination results. The test result query function is one of the important components of the online test system. Users can query their test scores and rankings by entering relevant information. This article will introduce how to use MySQL to create the examination results query table structure of the online examination system, and provide specific code examples.

In MySQL, we can use SQL statements to create table structures. First, we need to determine the fields of the exam results query table to meet our needs. Common fields include candidate name, candidate student number, examination subject, examination results, examination date, etc. The specific table structure can be created according to the following code example:

CREATE TABLE exam_result (
   id INT AUTO_INCREMENT PRIMARY KEY,
   student_name VARCHAR(50) NOT NULL,
   student_id VARCHAR(20) NOT NULL,
   subject VARCHAR(50) NOT NULL,
   score INT NOT NULL,
   exam_date DATE
);

In the table structure created above, the id field is an auto-incremented primary key that can uniquely identify each record. The student_name field is used to store the candidate's name, the student_id field is used to store the candidate's student number, the subject field is used to store the examination subject, and the score field is used to store the candidate's name Exam scores, exam_date field stores the exam date.

Next, we can test whether the table structure is correct by inserting data. The following is an example SQL statement for inserting data:

INSERT INTO exam_result (student_name, student_id, subject, score, exam_date)
VALUES ('张三', '20210001', '数学', 85, '2021-05-01'),
       ('李四', '20210002', '英语', 92, '2021-05-02'),
       ('王五', '20210003', '语文', 78, '2021-05-02');

The above SQL statement will insert three pieces of exam result data into the exam_result table, including candidate name, candidate student number, exam subject, and exam Scores and exam dates.

After completing the creation of the above table structure and data, we can query the exam results. The following is a simple query example to query the candidate's test scores and rankings through the candidate's student number:

SELECT student_name, score,
       (SELECT COUNT(*) FROM exam_result WHERE score >= er.score) AS ranked
FROM exam_result as er
WHERE student_id = '20210001';

The above SQL statement will return the name, score, and ranking of the candidate whose student number is '20210001'. Subquery (SELECT COUNT(*) FROM exam_result WHERE score >= er.score) is used to calculate the number of records that are not lower than the candidate's score, that is, the ranking. Through this query statement, we can easily query the score and ranking information of a certain candidate.

In summary, this article introduces how to use MySQL to create the examination results query table structure of the online examination system, and provides specific code examples. Through these code examples, we can create a database table that can meet the examination results query function, and can easily perform related query operations. I hope this article will help you understand the database design of the online examination system.

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