我们怎样才能修改MySQL视图的定义而不删除它呢？

ALTER VIEW view_name AS
SELECT column1,column2…
FROM table
WHERE conditions;

mysql> Select * from Info;
+------+---------+------------+
| Id   | Name    | Subject    |
+------+---------+------------+
| 101  | YashPal | History    |
| 105  | Gaurav  | Literature |
| 125  | Raman   | Computers  |
| 130  | Ram     | Computers  |
+------+---------+------------+
4 rows in set (0.01 sec)

mysql> Alter view info AS SELECT ID, NAME, SUBJECT, ADDRESS from student_info;
Query OK, 0 rows affected (0.07 sec)

mysql> Select * from info;
+------+---------+------------+------------+
| ID   | NAME    | SUBJECT    | ADDRESS    |
+------+---------+------------+------------+
| 101  | YashPal | History    | Amritsar   |
| 105  | Gaurav  | Literature | Chandigarh |
| 125  | Raman   | Computers  | Shimla     |
| 130  | Ram     | Computers  | Jhansi     |
+------+---------+------------+------------+
4 rows in set (0.00 sec)