티스토리 뷰
Database2 - Mysql
2020-03-23
2nd day
JOIN
topic 테이블 ↓
id | title | description | created | author_id |
---|---|---|---|---|
1 | MySQL | MySQL is... | 2018-01-01 12:10:11 | 1 |
2 | Oracle | Oracle is... | 2018-01-03 13:01:10 | 1 |
3 | SQL Server | SQL Server is... | 2018-01-20 11:01:10 | 2 |
4 | PostgreSQL | PostgreSQL is... | 2018-01-23 01:03:03 | 3 |
5 | MongoDB | MongoDB is... | 2018-01-30 12:31:03 | 1 |
author 테이블 ↓
id | name | profile |
---|---|---|
1 | egoing | developer |
2 | duru | data administrator |
3 | taeho | data scientist, developer |
author_id와 author.id를 일치시키기 위해 아래 쿼리 실행
SELECT topic.id AS 'topic.id', -- AS : 이름지정 title, description, created, name, profile FROM topic LEFT JOIN author -- INNER, LEFT, RIGHT 등등.. 벤다이어그램을 생각 ON topic.author_id=author.id; -- topic테이블과 author테이블의 공통 키값을 기준으로 한다.
결과물
topic.id | title | description | created | name | profile |
---|---|---|---|---|---|
1 | MySQL | MySQL is... | 2018-01-01 12:10:11 | egoing | developer |
2 | Oracle | Oracle is... | 2018-01-03 13:01:10 | egoing | developer |
5 | MongoDB | MongoDB is... | 2018-01-30 12:31:03 | egoing | developer |
3 | SQL Server | SQL Server is... | 2018-01-20 11:01:10 | duru | data administrator |
4 | PostgreSQL | PostgreSQL is... | 2018-01-23 01:03:03 | taeho | data scientist, developer |
참고 이미지
INNER JOIN
LEFT, RIGHT JOIN
Link
공지사항
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