알고리즘 스택/ 큐/ 그래프 vs matrix 개념을 알고 코드를 분석한다
linkedlist vs Arraylist 차이
collection = list, map, set 차이
-db 와의 연결관계 확인
-callbac kvs promise hell
https://siyoon210.tistory.com/130
https://jinyoungchoi95.tistory.com/10
https://snowple.tistory.com/272?category=349295
http://www.tcpschool.com/mysql/mysql_basic_syntax
https://www.codeit.kr/courses/sql-database-for-data-analytics/topics/data-analysis-using-sql?utm_source=google_paid&utm_medium=sa_pc&utm_campaign=sa&utm_term=sql%20%EA%B5%90%EC%9C%A1&utm_content=sql&gclid=Cj0KCQjw4PKTBhD8ARIsAHChzRK_3mjrdS_f1s9AffYXo5rNhQwmLdiY8W3Dc4JnHAii82HZUCvAoAsaAn4lEALw_wcB
https://drive.google.com/file/d/199lUBGRsRxOQWMz6l-aTcV-YyIFU078E/view