How to get column data as row - mysql

Question

I have the following problem in MySQL 5.5. Here's my table.
Suppose i have a table With 'Names' with columns Rank,NAME and data in table
When i run the query it will give result as
select *from name
Rank | NAME
-------------
1 | A
1 | B
1 | C
2 | D
2 | E
2 | F
3 | G
3 | H
3 | I
Now this is of course a terribly inconvenient way to organize data, but that's how the data happened to come in (and will continue to come in).
I need to be able to throw at it a way with list of NAMES corresponding to their Respective Rank as shown below
Rank | Name | Name | Name
-----------------------------------
1 | A | B | C
2 | D | E | F
3 | G | H | I
I have query like
select
case when rank=1 then name else null end as 1,
case when rank=2 then name else null end as 2,
case when rank=3 then name else null end as 3
from name
The name with same ranks need to be brought and showed in the same row.i cant estimate the last rank will obtained by the student so i cant pass rank values manually by using 'IN' operator.Since the rank values are unpredictable i need to get them in cross tab view dynamically withh respective to their ranks.
I've tried with all kinds of dynamic crosstab-generating queries (yes, I've seen them all), but I don't have Any sucess. Please help me. Thank you!

Answer 1

DROP TABLE IF EXISTS my_table;
CREATE TABLE my_table
(rank INT NOT NULL
,name CHAR(1) NOT NULL
,PRIMARY KEY(rank,name)
);
INSERT INTO my_table VALUES
(1 ,'A'),
(1 ,'B'),
(1 ,'C'),
(2 ,'D'),
(2 ,'E'),
(2 ,'F'),
(3 ,'G'),
(3 ,'H'),
(3 ,'I');
SELECT * FROM my_table;
+------+------+
| rank | name |
+------+------+
| 1 | A |
| 1 | B |
| 1 | C |
| 2 | D |
| 2 | E |
| 2 | F |
| 3 | G |
| 3 | H |
| 3 | I |
+------+------+
SELECT x.*,COUNT(*) subrank FROM my_table x JOIN my_table y ON y.rank = x.rank AND y.name <= x.name GROUP BY x.rank,x.name;
+------+------+---------+
| rank | name | subrank |
+------+------+---------+
| 1 | A | 1 |
| 1 | B | 2 |
| 1 | C | 3 |
| 2 | D | 1 |
| 2 | E | 2 |
| 2 | F | 3 |
| 3 | G | 1 |
| 3 | H | 2 |
| 3 | I | 3 |
+------+------+---------+
SELECT rank
, MAX(CASE WHEN subrank = 1 THEN name END) name1
, MAX(CASE WHEN subrank = 2 THEN name END) name2
, MAX(CASE WHEN subrank = 3 THEN name END) name3
FROM
( SELECT x.*
, COUNT(*) subrank
FROM my_table x
JOIN my_table y
ON y.rank = x.rank
AND y.name <= x.name
GROUP
BY x.rank
, x.name
) a
GROUP
BY rank;
+------+-------+-------+-------+
| rank | name1 | name2 | name3 |
+------+-------+-------+-------+
| 1 | A | B | C |
| 2 | D | E | F |
| 3 | G | H | I |
+------+-------+-------+-------+