컬럼명/컬럼 타입 변경, 컬럼 추가/삭제

1. 컬럼명 변경

ALTER TABLE table_name CHANGE [COLUMN] old_col_name new_col_name column_definition [FIRST | AFTER col_name]

ALTER TABLE user CHANGE username user_id varchar(30);

 

2. 컬럼  순서 변경

ALTER TABLE table_name MODIFY [COLUMN] col_name column_definition [FIRST | AFTER col_name]

ALTER TABLE user MODIFY nickname varchar(30) AFTER password;

 

3. 컬럼 디폴트값 변경

ALTER TABLE table_name ALTER [COLUMN] col_name {SET DEFAULT {literal | (expr)} | DROP DEFAULT}

ALTER TABLE user ALTER age SET DEFAULT NULL

4. 컬럼 타입 변경

ALTER TABLE table_name MODIFY col_name col_definition

ALTER TABLE user MODIFY nickname varchar(30);

5. 컬럼 추가

ALTER TABLE table_name ADD [COLUMN] col_name column_definition [FIRST | AFTER col_name]

ALTER TABLE user ADD location varchar(50) DEFAULT NULL [AFTER 'username'];

 

6. 컬럼 삭제

ALTER TABLE table_name DROP [COLUMN] col_name

ALTER TABLE user DROP location;

참조 URL

• https://juyoung-1008.tistory.com/17
• https://dev.mysql.com/doc/refman/8.0/en/alter-table.html

MySQL 컬럼명 변경, 컬럼 타입 변경, 컬럼 추가, 컬럼 삭제