Obtain the average price of each piece (show only the piece code and the average price).
| SELECT piece, price FROM provides
| GROUP piece, price AVG BY piece
4 rows 0 msec
| GROUP piece, price AVG BY piece
4 rows 0 msec
| piece | price-avg |
|---|---|
| 1 | 12.5 |
| 2 | 16.333333333333 |
| 3 | 47.5 |
| 4 | 6 |