Agrupar películas

Toma de decisiones basada en datos en SQL

Bart Baesens

Professor Data Science and Analytics

Aplicaciones

Preferencias de los clientes por país o género.
La popularidad de las películas por género o año de estreno.
El precio medio de las películas por género.

Tabla: películas_seleccionadas

GROUP BY

SELECT genre
FROM movies_selected
GROUP BY genre;

| genre       |
|-------------|
| Drama       |
| Fantasy     |
| Sci-Fiction |
| Animation   |
| Romance     |

Precio medio de alquiler

SELECT genre, 
       AVG(renting_price) AS avg_price
FROM movies_selected
GROUP BY genre;

| genre       | avg_price   |
|-------------|-------------|
| Drama       | 2.865       |
| Fantasy     | 2.69        |
| Sci-Fiction | 2.87        |
| Animation   | 2.923333333 |
| Romance     | 2.99        |

tabla movies_selected

tabla movies_selected dividida

Precio medio de alquiler y número de películas

SELECT genre, 
       AVG(renting_price) AS avg_price, 
       COUNT(*) AS number_movies
FROM movies_selected
GROUP BY genre

| genre       | avg_price     | number_movies |
|-------------|---------------|---------------|
| Drama       | 2.865         | 4             |
| Fantasy     | 2.69          | 3             |
| Sci-Fiction | 2.87          | 2             |
| Animation   | 2.923333333   | 3             |
| Romance     | 2.99          | 1             |

HAVING

SELECT genre, 
       AVG(renting_price) avg_price, 
       COUNT(*) number_movies
FROM movies
GROUP BY genre
HAVING COUNT(*) > 2;

| genre     | avg_price     | number_movies |
|-----------|---------------|---------------|
| Drama     | 2.865         | 4             |
| Fantasy   | 2.69          | 3             |
| Animation | 2.923333333   | 3             |

¡Vamos a practicar!

Toma de decisiones basada en datos en SQL