팁
가장 rows가 많은 테이블을 먼저 배치해라(쿼리 옵티마이저)
INNER JOIN
- 원래 아는 그거
OUTER JOIN
SELF JOIN
SELECT p.name AS parent, c.name AS child
FROM tree c, tree p
WHERE …Other articles
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[MySQL] mysql sample database
docker-compose up -d docker exec -it mysql_sample bash cd usr/src/test_db mysql -uroot -pMyPassword -t < employees.sql
read more[MySQL] 실행계획
실행계획
- id: select id
- select_type: SIMPLE, UNION, SUBQUERY, etc
- type: data scan type (const, ALL, ref, range, index, fulltext, etc)
- const: 클러스터드 인덱스, 유니크 인덱스를 사용했을 때
- ALL: 인덱스를 타 …
[MySQL] STORED ROUTINE
A stored routine is either a procedure or a function. A procedure is invoked using a CALL statement and can only pass back values using output variables. A function can be called from inside a statement just like any other function and can return a scalar value.
read more[MySQL] 트랜잭션
트랜잭션
- SHOW VARIABLES LIKE '%COMMIT%'
- 현재 커밋과 관련된 설정정보 확인
- START TRANSACTION
- COMMIT
- ROLLBACK
SHOW VARIABLES LIKE '%COMMIT%' autocommit ON <- 여기 binlog_group_commit_sync_delay 0 binlog_group_commit_sync_no_delay_count 0 binlog_order_commits ON innodb_api_bk_commit_interval 5 innodb_commit_concurrency 0 innodb_flush_log_at_trx_commit 1 original_commit_timestamp 36028797018963968read moreSTART TRANSACTION …[MySQL] UNION
UNION 과 UNION ALL의 차이
read moreUNION은 두 쿼리의 결과에서 중복되는 값을 삭제하여 나타냅니다.UNION ALL은 두 쿼리의 결과에서 중복되는 값을 모두 …[MySQL] VIEW
[MySQL] WITH