TIL 07 : mysql_UPDATE & DELETE

### UPDATE

+----+--------------+-------------------+---------------------+--------+---------------------------+
| id | title        | description       | created             | author | profile                   |
+----+--------------+-------------------+---------------------+--------+---------------------------+
|  1 | MySQL        | MySQL is ...      | 2021-08-27 20:46:55 | egoing | developer                 |
|  2 | Gunhee hello | Hello             | 2021-08-27 21:07:16 | egoing | developer                 |
|  3 | SQL Server   | SQL Server is ... | 2021-08-27 21:13:50 | duru   | database administrator    |
|  4 | PostgreSQL   | PostgreSQL is ... | 2021-08-27 21:15:49 | taeho  | data scientist, developer |
|  5 | MongoDB      | MongoDB is ...    | 2021-08-27 21:16:03 | egoing | developer                 |
+----+--------------+-------------------+---------------------+--------+---------------------------+

• row의 정보 바꾸기
  • UPDATE topic SET description='Today I Learned', title='Velog' WHERE id =2;

mysql> UPDATE topic SET description='Today I Learned', title='Velog' WHERE id=2;

mysql> SELECT * FROM topic;
+----+------------+-------------------+---------------------+--------+---------------------------+
| id | title      | description       | created             | author | profile                   |
+----+------------+-------------------+---------------------+--------+---------------------------+
|  1 | MySQL      | MySQL is ...      | 2021-08-27 20:46:55 | egoing | developer                 |
|  2 | Velog      | Today I Learned   | 2021-08-27 21:07:16 | egoing | developer                 |
|  3 | SQL Server | SQL Server is ... | 2021-08-27 21:13:50 | duru   | database administrator    |
|  4 | PostgreSQL | PostgreSQL is ... | 2021-08-27 21:15:49 | taeho  | data scientist, developer |
|  5 | MongoDB    | MongoDB is ...    | 2021-08-27 21:16:03 | egoing | developer                 |
+----+------------+-------------------+---------------------+--------+---------------------------+

• 여기서 WHERE을 빼먹으면 대참사가 발생한다

DELETE

+----+------------+-------------------+---------------------+--------+---------------------------+
| id | title      | description       | created             | author | profile                   |
+----+------------+-------------------+---------------------+--------+---------------------------+
|  1 | MySQL      | MySQL is ...      | 2021-08-27 20:46:55 | egoing | developer                 |
|  2 | Velog      | Today I Learned   | 2021-08-27 21:07:16 | egoing | developer                 |
|  3 | SQL Server | SQL Server is ... | 2021-08-27 21:13:50 | duru   | database administrator    |
|  4 | PostgreSQL | PostgreSQL is ... | 2021-08-27 21:15:49 | taeho  | data scientist, developer |
|  5 | MongoDB    | MongoDB is ...    | 2021-08-27 21:16:03 | egoing | developer                 |
+----+------------+-------------------+---------------------+--------+---------------------------+

• 하나의 행 지우기
  • DELETE FROM topic이름 WHERE id=5;

mysql> DELETE FROM topic WHERE id=5;

mysql> SELECT * FROM topic;
+----+------------+-------------------+---------------------+--------+---------------------------+
| id | title      | description       | created             | author | profile                   |
+----+------------+-------------------+---------------------+--------+---------------------------+
|  1 | MySQL      | MySQL is ...      | 2021-08-27 20:46:55 | egoing | developer                 |
|  2 | Velog      | Today I Learned   | 2021-08-27 21:07:16 | egoing | developer                 |
|  3 | SQL Server | SQL Server is ... | 2021-08-27 21:13:50 | duru   | database administrator    |
|  4 | PostgreSQL | PostgreSQL is ... | 2021-08-27 21:15:49 | taeho  | data scientist, developer |
+----+------------+-------------------+---------------------+--------+---------------------------+