DB/SQL

Data mining

Ref

http://dm.snu.ac.kr/ko/

https://towardsdatascience.com/your-ultimate-data-mining-machine-learning-cheat-sheet-9fce3fa16

https://medium.com/mit-technology-review/data-mining-reveals-fundamental-pattern-of-human-thinking-7fc1d5e1d8b

Query Performance

Ref

join

• [SQL-TUNING] 조인 튜닝 - NL & SORT MERGE

• [SQL-TUNING] 조인 튜닝 - HASH Join

• [SQL-TUNING] 조인 튜닝 - Sub Query

mysql workbench

• 7.2 Performance Schema Reports

• 7.3 Query Statistics

• 7.4 Visual Explain Plan

• 7.5 Tutorial: Using Explain to Improve Query Performance

Scan

• full scan

• range scan

word

• processure

• optimize

• query cost

• nested

• execution plan (query plan)

• index - primary key, foreign key

Prepared Statement

Ref

• https://blog.naver.com/skinfosec2000/220482240245

SQL

Ref

SQL Coding Best Practices for Writing Clean Code

MySQL data count in 10 minute intervals

ref

MySQL 계산하거나 문자열을 결합해서 표시하기, MySQL 함수 사용하기

OracleSQL - 중첩 그룹함수 / 분석함수

sql group by 2개 이상 : 나눌 기준을 select 절에도 똑같이 적어주면 된다.