How to implement intra-group sorting by MySQL

How does MySQL implement intra-group sorting? This problem may be often seen in our daily study or work. I hope you can gain a lot from this question. The following is the reference content that the editor brings to you, let's take a look at it!

Suppose the table is student, and the data are as follows:

   We want to achieve the rank () function in Oracle in MySQL, that is, sorting within the group, specifically: ranking the students (name) according to the course (course) in the student table by the score (score).

   first creates a new stored procedure realize_rank_in_MySQL with the following code:

DROP PROCEDURE IF EXISTS realize_rank_in_MySQL;DELIMITER;; CREATE PROCEDURE realize_rank_in_MySQL () BEGIN DECLARE i int; SET i = 0; WHILE I < (select count (DISTINCT course) from student) DO SET @ ROW = 0; INSERT INTO student_rank SELECT *, (@ ROW:=@ROW+1) AS rank FROM student WHERE course= (select DISTINCT course from student limit iMagin1) ORDER BY score DESC Set I = I + 1; END WHILE;END;;DELIMITER

Then enter the following query statement:

Drop table if exists student_rank;create table student_rank like student;alter table student_rank add rank int;call realize_rank_in_MySQL;select * from student_rank

The    results are as follows:

Note: the ranking here does not achieve the same score as the same ranking.

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