Data-Driven Decision Making in SQL
Bart Baesens
Professor Data Science and Analytics
Preferences of customers by country or gender.
The popularity of movies by genre or year of release.
The average price of movies by genre.
SELECT genre
FROM movies_selected
GROUP BY genre;
| genre |
|-------------|
| Drama |
| Fantasy |
| Sci-Fiction |
| Animation |
| Romance |
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 |
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 |
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 |
Data-Driven Decision Making in SQL