我有下foo表：
+----+--------+-------+
| id | name | qty |
+----+--------+-------+
| 1 | John | 3 |
| 2 | John | 1 |
| 3 | Mary | 5 |
| 4 | Mary | 2 |
| 5 | Gary | 3 |
| 6 | Gary | 4 |
| 7 | Gary | 5 |
+----+--------+-------+
我只想选择id和name最小Qty分组 by name，结果如下：
+----+--------+
| id | name |
+----+--------+
| …