MySql column의 type check 방법

 

Summry

본 문서에서는 테이블을 만들고 나서 칼럼의 타입을 확인하고자 할 때 사용할 방법들을 정리한다.

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1. SHOW COLUMNS

전체 field 보기

mysql> SHOW COLUMNS FROM `user_info`;
+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| idx          | int(11)      | NO   | PRI | NULL    | auto_increment |
| device_token | varchar(255) | YES  | UNI | NULL    |                |
+--------------+--------------+------+-----+---------+----------------+
2 rows in set (0.004 sec)

특정 field만 보기

mysql> SHOW COLUMNS FROM `user_info` LIKE 'idx';
+-------+---------+------+-----+---------+----------------+
| Field | Type    | Null | Key | Default | Extra          |
+-------+---------+------+-----+---------+----------------+
| idx   | int(11) | NO   | PRI | NULL    | auto_increment |
+-------+---------+------+-----+---------+----------------+
1 row in set (0.004 sec)

2. desc

mysql> desc user_info;
+--------------+--------------+------+-----+---------+----------------+
| Field        | Type         | Null | Key | Default | Extra          |
+--------------+--------------+------+-----+---------+----------------+
| idx          | int(11)      | NO   | PRI | NULL    | auto_increment |
| device_token | varchar(255) | YES  | UNI | NULL    |                |
+--------------+--------------+------+-----+---------+----------------+
2 rows in set (0.006 sec)

3. information_schema

전체 field 보기

mysql> SELECT DATA_TYPE FROM information_schema.COLUMNS WHERE TABLE_NAME='user_info';
+-----------+
| DATA_TYPE |
+-----------+
| int       |
| varchar   |
+-----------+
2 rows in set (0.005 sec)

특정 field만 보기

mysql> SELECT DATA_TYPE FROM information_schema.COLUMNS WHERE TABLE_NAME='user_info' AND COLUMN_NAME='device_token';
+-----------+
| DATA_TYPE |
+-----------+
| varchar   |
+-----------+
1 row in set (0.005 sec)

전체 field 보기

mysql> SELECT COLUMN_TYPE FROM information_schema.COLUMNS WHERE TABLE_NAME='user_info';
+--------------+
| COLUMN_TYPE  |
+--------------+
| int(11)      |
| varchar(255) |
+--------------+
2 rows in set (0.005 sec)

특정 field만 보기

mysql> SELECT COLUMN_TYPE FROM information_schema.COLUMNS WHERE TABLE_NAME='user_info' AND COLUMN_NAME='device_token';
+--------------+
| COLUMN_TYPE  |
+--------------+
| varchar(255) |
+--------------+
1 row in set (0.005 sec)

Reference

MySQL 컬럼 자료형 확인 - ZETAWIKI
Mysql 기본 쿼리 명령어 - 자유코딩