MySQL 컬럼명 변경, 컬럼 자료형 변경

1 개요

MySQL 컬럼 자료형 변경

원자료 손실에 주의 ★

ALTER TABLE `테이블명` CHANGE `컬럼명` `컬럼명` 자료형

2 예시

mysql> DESC employee;
+---------------+-------------+------+-----+---------+-------+
| Field         | Type        | Null | Key | Default | Extra |
+---------------+-------------+------+-----+---------+-------+
| id            | int(11)     | NO   | PRI | NULL    |       |
| name          | varchar(16) | NO   |     | NULL    |       |
| department_id | int(11)     | NO   |     | NULL    |       |
+---------------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mysql> ALTER TABLE `employee` CHANGE `department_id` `department_id` VARCHAR(16) NOT NULL;
Query OK, 4 rows affected (0.08 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> DESC employee;
+---------------+-------------+------+-----+---------+-------+
| Field         | Type        | Null | Key | Default | Extra |
+---------------+-------------+------+-----+---------+-------+
| id            | int(11)     | NO   | PRI | NULL    |       |
| name          | varchar(16) | NO   |     | NULL    |       |
| department_id | varchar(16) | NO   |     | NULL    |       |
+---------------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

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