Which aggregate function to use in the following pivot clause? - database

Question

I have a table Players which has two columns : Name and Sport_Played.
Sample data would be like:
Name. Sport _played
Ravi Cricket
Raju Cricket
Ronaldo Football
Messi Football
Anand Chess
I want to pivot the table having columns as sport played and the columns should contain the names of players sorted ascendingly.
Cricket Football Chess
Raju Messi Anand
Ravi Ronaldo Null
The problem is that pivot requires an aggregate function. What aggregate function to use to display the names of players as part of column of sport played. Thanks.

Answer 1

Without an example of how you want your output it is difficult to know what you are intending but:
having columns as sport played and the columns should contain the names of players sorted ascendingly
You do not need to use PIVOT, you can use LISTAGG:
SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE players ( Name, Sport_played ) AS
SELECT 'Ravi', 'Cricket' FROM DUAL UNION ALL
SELECT 'Raju', 'Cricket' FROM DUAL UNION ALL
SELECT 'Ronaldo', 'Football' FROM DUAL UNION ALL
SELECT 'Messi', 'Football' FROM DUAL UNION ALL
SELECT 'Anand', 'Chess' FROM DUAL;
Query 1:
SELECT sport_played,
LISTAGG( name, ',' ) WITHIN GROUP ( ORDER BY name ) As names
FROM players
GROUP BY sport_played
Results:
| SPORT_PLAYED | NAMES |
|--------------|---------------|
| Chess | Anand |
| Cricket | Raju,Ravi |
| Football | Messi,Ronaldo |
Update:
SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE players ( Name, Sport_played ) AS
SELECT 'Ravi', 'Cricket' FROM DUAL UNION ALL
SELECT 'Raju', 'Cricket' FROM DUAL UNION ALL
SELECT 'Ronaldo', 'Football' FROM DUAL UNION ALL
SELECT 'Messi', 'Football' FROM DUAL UNION ALL
SELECT 'Anand', 'Chess' FROM DUAL;
Query 1:
SELECT *
FROM ( SELECT p.*,
ROW_NUMBER() OVER ( PARTITION BY Sport_played
ORDER BY name ) AS rn
FROM players p )
PIVOT (
MAX( Name )
FOR Sport_Played IN (
'Cricket' As Cricket,
'Football' As Football,
'Chess' AS Chess
)
)
Results:
| RN | CRICKET | FOOTBALL | CHESS |
|----|---------|----------|--------|
| 1 | Raju | Messi | Anand |
| 2 | Ravi | Ronaldo | (null) |
You can use any (string) aggregation function in the PIVOT including MAX(name), MIN(name) or even LISTAGG( name, ',' ) WITHIN GROUP ( ORDER BY Name ). The ROW_NUMBER() analytic function will generate a unique number-per-sport so the aggregation function will only ever work on a single value so it does not matter what aggregation function is used.