**Aggregate functions** compute a single result from a set of multiple input values. You can think of aggregate data as data collected from multiple rows at a time. In this lesson, we’ll continue learning about aggregate functions by focusing on conditionals, sums, and combining aggregate functions.

**Conditional Aggregates** are aggregate functions that compute a result set based on a given set of conditions.

If you are new to aggregate functions, we recommend you complete this course first.

### Instructions

**1.**

The `count`

function is an aggregate function, since it aggregates data from multiple rows.

Count the number of rows in the `flights`

table, representing the total number of flights contained in the table.