Ordering
Eliminating duplicate results
Aggregation
15. Find the sum
Grouping
HAVING: filtering and ordering groups
Let's practice

## Instruction

That's right. The last function that we'll discuss is sum().

Examine the example:

SELECT
sum(total_sum)
FROM orders
WHERE customer_id = 100;


The above instruction will find the total sum of all orders placed by the customer with id 100.

## Exercise

Find the sum of all salaries in the Marketing department in 2014. Remember to put the department name in inverted commas!

### Stuck? Here's a hint!

Type:

SELECT
sum(salary)
FROM employees
WHERE year = 2014 AND department LIKE 'Marketing';