I have the following dataset and i would like to convert rows into columns
+----------+---------+
| assoc | player |
+----------+---------+
| 1 | 12 |
| 1 | 20 |
| 1 | 30 |
| 2 | 51 |
| 2 | 52 |
| 2 | 63 |
+----------+---------+
Making the view looks like
+----------+----------+----------+----------+
| assoc | player1 | player2 | player3 |
+----------+----------+----------+----------+
| 1 | 12 | 20 | 30 |
| 2 | 51 | 52 | 63 | |
+----------+----------+----------+----------+