Up: SQL,structured_query_language

https://www.khanacademy.org/computing/computer-programming/sql/sql-basics/v/welcome-to-sql

https://www.khanacademy.org/computing/computer-programming/sql/sql-basics/pt/creating-a-table-and-inserting-data

create table groceries (id integer primary key, name text, quantity integer);

하면 schema를 만듦:
groceries (3 rows)

id (PK)	INTEGER
name	TEXT
quantity INTEGER

insert into groceries values (1, "Bananas", 4);
insert into groceries values (2, "peanut butter", 1);
insert into groceries values (3, "dark chocolate bars", 2);

들어간 자료:

id	name	quantity
1	Bananas	4
2	Peanut Butter	1
3	Dark chocolate bars	2

https://www.khanacademy.org/computing/computer-programming/sql/sql-basics/pt/querying-the-table
select * from groceries where XXX > 5 order by XXX;

https://www.khanacademy.org/computing/computer-programming/sql/sql-basics/pc/challenge-box-office-hits-database

https://www.khanacademy.org/computing/computer-programming/sql/sql-basics/pt/aggregating-data
select sum(XXX) from groceries;
select max(XXX) from groceries;

SELECT aisle, SUM(quantity) FROM groceries GROUP BY aisle;

https://www.khanacademy.org/computing/computer-programming/sql/sql-basics/v/s-q-l-or-sequel

https://www.khanacademy.org/computing/computer-programming/sql/more-advanced-sql-queries/pt/more-complex-queries-with-andor

CREATE TABLE exercise_logs
    (id INTEGER PRIMARY KEY AUTOINCREMENT,
    type TEXT,
    minutes INTEGER, 
    calories INTEGER,
    heart_rate INTEGER);


INSERT INTO exercise_logs(type, minutes, calories, heart_rate) VALUES ("biking", 30, 100, 110);
INSERT INTO exercise_logs(type, minutes, calories, heart_rate) VALUES ("biking", 10, 30, 105);
INSERT INTO exercise_logs(type, minutes, calories, heart_rate) VALUES ("dancing", 15, 200, 120);

SELECT * FROM exercise_logs WHERE calories > 50 ORDER BY calories;

/* AND */
SELECT * FROM exercise_logs WHERE calories > 50 AND minutes < 30;

/* OR */
SELECT * FROM exercise_logs WHERE calories > 50 OR heart_rate > 100;