aqui você pode ver os backticks
alter table `data` add `timestamp` VARCHAR(20);
AMOSTRA
MariaDB []> desc data;
+-------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| e | enum('x1','x2','x3') | YES | | NULL | |
+-------+----------------------+------+-----+---------+----------------+
2 rows in set (0.01 sec)
MariaDB []> alter table `data` add `timestamp` VARCHAR(20);
Query OK, 0 rows affected (0.05 sec)
Records: 0 Duplicates: 0 Warnings: 0
MariaDB []> desc data;
+-----------+----------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-----------+----------------------+------+-----+---------+----------------+
| id | int(11) unsigned | NO | PRI | NULL | auto_increment |
| e | enum('x1','x2','x3') | YES | | NULL | |
| timestamp | varchar(20) | YES | | NULL | |
+-----------+----------------------+------+-----+---------+----------------+
3 rows in set (0.01 sec)
Dados da tabela
MariaDB [who]> select * from `data`;
+----+------+-----------+
| id | e | timestamp |
+----+------+-----------+
| 1 | x1 | NULL |
| 2 | x2 | NULL |
+----+------+-----------+
2 rows in set (0.00 sec)
MariaDB [who]>
