views:

39

answers:

1

Hi, I am not an expert in mysql.I need to find out rank of customers.Here I am adding the corresponding sql query for my requirement.Please help me to convert it to mysql.

 SELECT RANK() OVER (PARTITION BY Gender ORDER BY Age) AS [Partition by Gender], 
   FirstName, 
   Age,
   Gender FROM Person

.Is there any function to find out rank in mysql?

Thank you

+2  A: 

One option is to use a ranking variable, such as the following:

SELECT    first_name,
          age,
          gender,
          @curRank := @curRank + 1 AS rank
FROM      person p, (SELECT @curRank := 0) r
ORDER BY  age;

The (SELECT @curRank := 0) part allows the variable initialization without requiring a separate SET command.

Test case:

CREATE TABLE person (id int, first_name varchar(20), age int, gender char(1));

INSERT INTO person VALUES (1, 'Bob', 25, 'M');
INSERT INTO person VALUES (2, 'Jane', 20, 'F');
INSERT INTO person VALUES (3, 'Jack', 30, 'M');
INSERT INTO person VALUES (4, 'Bill', 32, 'M');
INSERT INTO person VALUES (5, 'Nick', 22, 'M');
INSERT INTO person VALUES (6, 'Kathy', 18, 'F');
INSERT INTO person VALUES (7, 'Steve', 36, 'M');
INSERT INTO person VALUES (8, 'Anne', 25, 'F');

Result:

+------------+------+--------+------+
| first_name | age  | gender | rank |
+------------+------+--------+------+
| Kathy      |   18 | F      |    1 |
| Jane       |   20 | F      |    2 |
| Nick       |   22 | M      |    3 |
| Bob        |   25 | M      |    4 |
| Anne       |   25 | F      |    5 |
| Jack       |   30 | M      |    6 |
| Bill       |   32 | M      |    7 |
| Steve      |   36 | M      |    8 |
+------------+------+--------+------+
8 rows in set (0.02 sec)
Daniel Vassallo
+1 for the devious inline initialization, that's a beautiful trick.
Charles
Excellent answer.Thank you so much....
Ajith
Didn't he ask for a partition though? My understanding of partitions is that the result set would have separate rankings for male and female.
Jesse Dhillon
@Jesse: If that is the case, I recently answered a similar question: http://stackoverflow.com/questions/3162389/multiple-ranks-in-one-table/
Daniel Vassallo