🕵️♀️ Task
You can calculate the sum of values in a particular column within a collection with .sum. It returns a single value (Integer or Float).
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| id | title | year | duration | description | image | director_id |
|---|
| id | name | dob | bio | image |
|---|
| id | name | dob | bio | image |
|---|---|---|---|---|
| 557 | Lea Thompson | 1961-05-31 | Lea Katherine Thompson was ... | http://ia.media-imdb.com/im... |
| 558 | Crispin Glover | 1964-04-20 | While he's never been a typ... | http://ia.media-imdb.com/im... |
| 622 | Wanja Mues | http://ia.media-imdb.com/im... | ||
| 477 | Vin Diesel | 1967-07-18 | Vin Diesel was raised by hi... | http://ia.media-imdb.com/im... |
| 478 | Giovanni Ribisi | 1974-12-17 | http://ia.media-imdb.com/im... | |
| 479 | Jeremy Davies | 1969-10-08 | Jeremy Davies attended the ... | http://ia.media-imdb.com/im... |
| 480 | Matt Damon | 1970-10-08 | Matthew Paige Damon was bor... | http://ia.media-imdb.com/im... |
| 481 | Ted Danson | 1947-12-29 | Ted Danson is well known fo... | http://ia.media-imdb.com/im... |
| id | actor_id | movie_id | name |
|---|---|---|---|
| 488 | 440 | 34 | Jay 'Chef' Hicks |
| 489 | 441 | 34 | Lance B. Johnson |
| 490 | 243 | 34 | Tyrone 'Clean' Miller (as L... |
| 491 | 442 | 34 | Chief Phillips |
| 492 | 143 | 34 | Colonel Lucas |
| 493 | 443 | 34 | Photojournalist |
| 494 | 34 | 34 | General Corman |
| 495 | 444 | 34 | Jerry, Civilian |
Calculate the sum of ages for all users
User.all.sum(:age)
=> 4566
Calculate the sum of prices for all dishes
Dish.all.sum(:price)
=> 232