我们如何从 MySQL 表列中存储的数据中获取最后的字符数？

mysql> Select * from examination_btech;
+-----------+----------+--------+
| RollNo    | Name     | Course |
+-----------+----------+--------+
| 201712001 | Rahul    | B.tech |
| 201712002 | Raman    | B.tech |
| 201712003 | Sahil    | B.tech |
| 201712004 | Shalini  | B.tech |
| 201712005 | Pankaj   | B.tech |
| 201712006 | Mohan    | B.tech |
| 201712007 | Yash     | B.tech |
| 201712008 | digvijay | B.tech |
| 201712009 | Gurdas   | B.tech |
| 201712010 | Preeti   | B.tech |
+-----------+----------+--------+
10 rows in set (0.00 sec)

mysql> Select RIGHT(RollNo, 3) FROM examination_btech;
+------------------+
| RIGHT(RollNo, 3) |
+------------------+
| 001              |
| 002              |
| 003              |
| 004              |
| 005              |
| 006              |
| 007              |
| 008              |
| 009              |
| 010              |
+------------------+
10 rows in set (0.00 sec)