需求一：谁已经学完了

需求："哪些人已经把某条路线学完了？要人名和路线。"

查询结果有几行？

mysql> SELECT user_name, path_code FROM learning_record WHERE progress = 100;
+-----------+-------------+
| user_name | path_code   |
+-----------+-------------+
| xiaoming  | l1_basic_01 |
| xiaohong  | l1_basic_01 |
| zhangsan  | l1_basic_01 |
| zhangsan  | l1_lang_01  |
+-----------+-------------+
mysql>