https://www.youtube.com/watch?v=7S_tz1z_5bA
어려워
what powers instagram
https://instagram-engineering.com/what-powers-instagram-hundreds-of-instances-dozens-of-technologies-adf2e22da2ad
INNER JOIN
SELECT *
FROM Orders
INNER JOIN Customers
ON Orders.CustomerID=Customers.CustomerID;
SELECT orders.id, orders.totalPice
FROM order_items
INNER JOIN orders
ON users.id = orders.user_id
WHERE users.username = "김코딩";
https://dimdim.tistory.com/entry/SQL-JOIN-%EC%A0%95%EB%A6%AC-Inner-Join-Outer-Join
JOIN
Q 5-2-2
const PART5_2_2 = SELECT user.name, user.email, role.name AS roleName FROM user LEFT JOIN role ON role.id = user.roleId;
Q 5-2-3.
https://www.w3schools.com/sql/sql_null_values.asp
https://www.youtube.com/watch?v=p3qvj9hO_Bo
SELECT category.name FROM category INNER JOIN content_category ON category.id = content_category.categoryId INNER JOIN content ON content_category.contentId = content.id INNER JOIN user ON content.userId = user.id WHERE user.name = 'jisungPark'
