Mega Code Archive
Advancing the rank only when values change
<![CDATA[
mysql>
mysql> CREATE TABLE testscore
-> (
-> subject INT UNSIGNED NOT NULL AUTO_INCREMENT,
-> age INT UNSIGNED NOT NULL,
-> sex ENUM('M','F') NOT NULL,
-> score INT,
-> PRIMARY KEY (subject)
-> );
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> INSERT INTO testscore (age,sex,score)
-> VALUES
-> (5,'M',5),
-> (5,'M',4),
-> (5,'F',6),
-> (5,'F',7),
-> (6,'M',8),
-> (6,'M',9),
-> (6,'F',4),
-> (6,'F',6),
-> (7,'M',8),
-> (7,'M',6),
-> (7,'F',9),
-> (7,'F',7),
-> (8,'M',9),
-> (8,'M',6),
-> (8,'F',7),
-> (8,'F',10),
-> (9,'M',9),
-> (9,'M',7),
-> (9,'F',10),
-> (9,'F',9)
-> ;
Query OK, 20 rows affected (0.00 sec)
Records: 20 Duplicates: 0 Warnings: 0
mysql>
mysql>
mysql> SET @rank = 0, @prev_val = NULL;
Query OK, 0 rows affected (0.00 sec)
mysql> SELECT @rank := IF(@prev_val=score,@rank,@rank+1) AS rank, @prev_val := score AS score FROM testscore ORDER BY sc
ore DESC;
+------+-------+
| rank | score |
+------+-------+
| 1 | 10 |
| 1 | 10 |
| 2 | 9 |
| 2 | 9 |
| 2 | 9 |
| 2 | 9 |
| 2 | 9 |
| 3 | 8 |
| 3 | 8 |
| 4 | 7 |
| 4 | 7 |
| 4 | 7 |
| 4 | 7 |
| 5 | 6 |
| 5 | 6 |
| 5 | 6 |
| 5 | 6 |
| 6 | 5 |
| 7 | 4 |
| 7 | 4 |
+------+-------+
20 rows in set (0.00 sec)
mysql>
mysql> drop table testscore;
Query OK, 0 rows affected (0.00 sec)
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