Multiple Ranks in one table

Question

Hi, I need the following, Can anyone please help me do it.

Rank   Cust_Type   Cust_Name   Revenue
1      Top         A           10000
2      Top         B           9000
3      Top         C           8000
1      Bottom      X           5000
2      Bottom      Y           6000
3      Bottom      Z           7000

I need separate ranks for Top and Bottom Cust_Type and all this is in MySQL.

Answer 1

This is a bit tricky. You may want to use variables, such as in the following example:

SELECT    ( 
            CASE cust_type 
            WHEN @curType 
            THEN @curRow := @curRow + 1 
            ELSE @curRow := 1 AND @curType := cust_type END
          ) + 1 AS rank,
          cust_type,
          cust_name,
          revenue
FROM      sales,
          (SELECT @curRow := 0, @curType := '') r
ORDER BY  cust_type DESC, revenue DESC;

The (SELECT @curRow := 0, @curType := '') r part allows the variable initialization without requiring a separate SET command.

Test case:

CREATE TABLE sales (cust_type varchar(10), cust_name varchar(10), revenue int);

INSERT INTO sales VALUES ('Top', 'A', 10000);
INSERT INTO sales VALUES ('Top', 'B', 9000);
INSERT INTO sales VALUES ('Top', 'C', 8000);
INSERT INTO sales VALUES ('Bottom', 'X', 5000);
INSERT INTO sales VALUES ('Bottom', 'Y', 6000);
INSERT INTO sales VALUES ('Bottom', 'Z', 7000);

Result:

+------+-----------+-----------+---------+
| rank | cust_type | cust_name | revenue |
+------+-----------+-----------+---------+
|    1 | Top       | A         |   10000 |
|    2 | Top       | B         |    9000 |
|    3 | Top       | C         |    8000 |
|    1 | Bottom    | Z         |    7000 |
|    2 | Bottom    | Y         |    6000 |
|    3 | Bottom    | X         |    5000 |
+------+-----------+-----------+---------+
6 rows in set (0.00 sec)

Another test case:

CREATE TABLE sales (cust_type varchar(10), cust_name varchar(10), revenue int);

INSERT INTO sales VALUES ('Type X', 'A', 7000);
INSERT INTO sales VALUES ('Type X', 'B', 8000);
INSERT INTO sales VALUES ('Type Y', 'C', 5000);
INSERT INTO sales VALUES ('Type Y', 'D', 6000);
INSERT INTO sales VALUES ('Type Y', 'E', 4000);
INSERT INTO sales VALUES ('Type Z', 'F', 4000);
INSERT INTO sales VALUES ('Type Z', 'G', 3000);

Result:

+------+-----------+-----------+---------+
| rank | cust_type | cust_name | revenue |
+------+-----------+-----------+---------+
|    1 | Type Z    | F         |    4000 |
|    2 | Type Z    | G         |    3000 |
|    1 | Type Y    | D         |    6000 |
|    2 | Type Y    | C         |    5000 |
|    3 | Type Y    | E         |    4000 |
|    1 | Type X    | B         |    8000 |
|    2 | Type X    | A         |    7000 |
+------+-----------+-----------+---------+
7 rows in set (0.00 sec)

You can obviously order the cust_type in ascending order instead of descending. I used descending just to have Top before Bottom in the original test case.

Answer 2

Sorry for not being specific. I need to query few tables to get this result using MySQL. Will your first solution work for my requirement?

Thanks.

Answer 3

What is not exactly clear is how the items should be ranked (I assumed by Revenue) or whether you are only pulling a certain number of values (e.g. the top 3 and the bottom 3) so I assumed you wanted all values. Given those assumptions,

Select Cust_Name, Cust_Type
    , (Select Count(*)
        From Table As T1
        Where T1.Revenue > T.Revenue ) + 1 As Rank
From Table As T
Where Cust_Type = 'Top'
Union All
Select Cust_Name, Cust_Type
    , (Select Count(*)
        From Table As T1
        Where T1.Revenue < T.Revenue ) + 1 As Rank
From Table As T
Where Cust_Type = 'Bottom'

If you were trying to do this in a single non-union query you could do:

Select Cust_Name, Cust_Type
    , Case Z.Cust_Type
        When 'Top' Then Z.TopRank
        Else Z.BottomRank
        End As Rank
From    (
        Select Cust_Name, Cust_Type
            , (Select Count(*)
                From Table As T1
                Where T1.Revenue > T.Revenue ) + 1 As TopRank
            , (Select Count(*)
                From Table As T1
                Where T1.Revenue < T.Revenue ) + 1 As BottomRank
        From Table As T
        ) As Z