我们如何更改表以添加MySQL虚拟GENERATED COLUMNS？
为了在表中添加MySQL虚拟GENERATEDCOLUMNS，我们可以使用与添加列相同的语法，只需在数据类型之后添加“AS(expression)”即可。它的语法如下-
语法
ALTER TABLE table_name ADD COLUMN column_name AS(expression);
示例
mysql> ALTER TABLE employee_data ADD COLUMN FULLName Varchar(200) AS(CONCAT_WS(" ", 'First_name','Last_name'));
Records: 0 Duplicates: 0 Warnings: 0
mysql> Describe employee_data;
+------------+--------------+------+-----+---------+-------------------+
| Field | Type | Null | Key | Default | Extra |
+------------+--------------+------+-----+---------+-------------------+
| ID | int(11) | NO | PRI | NULL | auto_increment |
| First_name | varchar(50) | NO | | NULL | |
| Last_name | varchar(50) | NO | | NULL | |
| FULL_NAME | varchar(90) | YES | | NULL | VIRTUAL GENERATED |
| FULLName | varchar(200) | YES | | NULL | VIRTUAL GENERATED |
+------------+--------------+------+-----+---------+-------------------+
5 rows in set (0.00 sec)