整张表其实有几列

再看看这张表本来有多少列：

整张表一共定义了几列？

mysql> DESC learning_record;
+-----------+-------------+------+-----+---------+-------+
| Field     | Type        | Null | Key | Default | Extra |
+-----------+-------------+------+-----+---------+-------+
| id        | int         | NO   | PRI | NULL    |       |
| user_id   | int         | NO   |     | NULL    |       |
| user_name | varchar(20) | NO   |     | NULL    |       |
| path_code | varchar(20) | NO   |     | NULL    |       |
| progress  | int         | NO   |     | NULL    |       |
| updated   | date        | NO   |     | NULL    |       |
+-----------+-------------+------+-----+---------+-------+
mysql>