我们如何修改表以添加 MySQL 存储的生成列?
mysqlmysqli database更新于 2024/2/25 10:00:00
要在表中添加 MySQL 存储的生成列，我们可以使用与添加列相同的语法，只需在数据类型后添加"AS(表达式)"即可。其语法如下 −
语法
ALTER TABLE table_name ADD COLUMN column_name AS(expression)STORED;
示例
mysql> ALTER TABLE employee_data_stored ADD COLUMN FULLName Varchar(200) AS (CONCAT_WS(" ", 'First_name','Last_name')) STORED;
Query OK, 2 rows affected (1.23 sec)
Records: 2 Duplicates: 0 Warnings: 0
mysql> Describe employee_data_stored;
+------------+--------------+------+-----+---------+------------------+
| 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 | STORED GENERATED |
| FULLName | varchar(200) | YES | | NULL | STORED GENERATED |
+------------+--------------+------+-----+---------+------------------+
5 rows in set (0.00 sec)
