Aggregation Intro

SQL lets you summarize and analyze large amounts of data using aggregate functions. These are special functions that return a single value based on multiple rows.

You won't use them for editing data. Instead, you use them to answer questions like:

• What's the total revenue?
• How many orders were placed?
• What's the average rating?

Aggregate functions are used in a SELECT statement to return a summary value.

You'll explore each aggregate function in more detail starting with COUNT() and SUM() in the next lesson.