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 c.parent = p.id
parent children
javascript change element id and name
javascript window.onload
javascript window.location.reload()
javascript async vs defer
javascript use strict
javascript data types: primative