L'evoluzione della mia carriera da back-end developer

Esercizio in MySQL

CREATE TABLE nazioni(
Code char(3) PRIMARY KEY,
Name char(52),
Continent enum('Asia','Europe','North America','Africa','Oceania','Antarctica','South America'),
Region char(26),
SurfaceArea float(10,2));

INSERT INTO nazioni(Code, Name, Continent, Region, SurfaceArea)
SELECT Code, Name, Continent, Region, SurfaceArea
FROM world.country;

DELETE FROM nazioni
WHERE Continent = 'Europe';

SELECT * 
FROM nazioni
ORDER BY Continent asc;

CREATE TABLE continenti(
NomeContinente char(52) PRIMARY KEY,
Superficie float(10,2));

INSERT INTO continenti(NomeContinente, Superficie)
VALUES ('Africa', 0), ('Asia', 0), ('Oceania', 0);


SELECT *
FROM continenti;

INSERT INTO continenti(NomeContinente, Superficie)
SELECT Continent, sum(SurfaceArea)
FROM nazioni
WHERE Continent IN ('Africa', 'Asia', 'Oceania')
GROUP BY Continent;