Aggregate Functions
Learn powerful functions for performing complex database operations with ease.
StartKey Concepts
Review core concepts you need to learn to master this subject
Column References
SUM()
Aggregate Function
MAX()
Aggregate Function
COUNT()
Aggregate Function
GROUP BY
Clause
MIN()
Aggregate Function
AVG()
Aggregate Function
HAVING
Clause
Column References
Column References
SELECT COUNT(*) AS 'total_movies',
rating
FROM movies
GROUP BY 2
ORDER BY 1;
The GROUP BY
and ORDER BY
clauses can reference the selected columns by number in which they appear in the SELECT
statement. The example query will count the number of movies per rating, and will:
GROUP BY
column2
(rating
)ORDER BY
column1
(total_movies
)
- 1We’ve learned how to write queries to retrieve information from the database. Now, we are going to learn how to perform calculations using SQL. Calculations performed on multiple rows of a table a…
- 7Oftentimes, we will want to calculate an aggregate for data with certain characteristics. For instance, we might want to know the mean IMDb ratings for all movies each year. We could calculate ea…
- 8Sometimes, we want to GROUP BY a calculation done on a column. For instance, we might want to know how many movies have IMDb ratings that round to 1, 2, 3, 4, 5. We could do this using the follow…
What you'll create
Portfolio projects that showcase your new skills
Trends in Startups
In this next Pro project, we're going to practice aggregate functions in SQL so you can hone your skills and feel confident taking them to the real world. Using these functions will combine row values together and return a single result. What's next? It's your first day as a TechCrunch reporter and you need SQL! You got this!
Analyze Hacker News Trends
Query Hacker News data using SQL to discover trends.
How you'll master it
Stress-test your knowledge with quizzes that help commit syntax to memory