Levelup

🕵️‍♀️ Task

Calculate the average duration for a record from the movies table

movies

You can calculate the average value in a particular column within a collection with .average. It returns a single value (Integer or Float).

id	title	year	duration	description	image	director_id
41	Spirited Away	2001	125	In the middle of her family...	http://ia.media-imdb.com/im...	30
42	Modern Times	1936	87	The Tramp struggles to live...	http://ia.media-imdb.com/im...	27
43	North by Northwest	1959	136	A hapless New York advertis...	http://ia.media-imdb.com/im...	21
44	Back to the Future	1985	116	A teenager is accidentally ...	http://ia.media-imdb.com/im...	15
45	Citizen Kane	1941	119	Following the death of a pu...	http://ia.media-imdb.com/im...	31
46	The Shining	1980	146	A family heads to an isolat...	http://ia.media-imdb.com/im...	28
47	Life Is Beautiful	1997	116	A Jewish man has a wonderfu...	http://ia.media-imdb.com/im...	32
48	The Pianist	2002	150	A Polish Jewish musician st...	http://ia.media-imdb.com/im...	33

id	name	dob	bio	image

id	name	dob	bio	image
41	John Travolta	1954-02-18	John Travolta first gained ...	http://ia.media-imdb.com/im...
42	Samuel L. Jackson	1948-12-21	Samuel L. Jackson usually p...	http://ia.media-imdb.com/im...
43	Tim Roth	1961-05-14	Often mistaken for an Ameri...	http://ia.media-imdb.com/im...
297	Frankie Faison	1949-06-10		http://ia.media-imdb.com/im...
298	Don Brockett	1930-01-30
299	Frank Seals Jr.
300	Stuart Rudin	1941-12-16
330	Stephen Baldwin	1966-05-12		http://ia.media-imdb.com/im...

id	actor_id	movie_id	name
41	36	3	Fanucci (as Gaston Moschin)
42	37	3	Rocco Lampone
43	38	3	Young Clemenza (as B. Kirby...
44	39	3	Genco
45	40	3	Young Mama Corleone (as Fra...
46	41	4	Vincent Vega
47	42	4	Jules Winnfield
48	43	4	Pumpkin / Ringo

Calculate the average age for all users

User.all.average(:age)
=> 27

Calculate the average price for all dishes

Dish.all.average(:price)
=> 5.69