Fundamentals of Data Analysis Functions in SQL

40. Functions in SQL

We’ve already seen aggregate functions in action:

SELECT COUNT(*) FROM users WHERE country = 'us'

An aggregate function returns a value for the group of records. In our case, ☝ it gives us a number of records.

There’s another type of function in SQL – scalar functions. Unlike aggregate functions, they receive input (a column value, a user-defined value, like string/number or no input at all) and return a single value or a set of values. In the previous lesson, we saw a type-casting operator ::. In fact, it’s a shortcut of a CAST scalar function:

...
“well worth the money”
Sign up and check out 37 free lessons and exercises.

Anatoli Makarevich, author of SQL Habit About SQL Habit

Hi, it’s Anatoli, the author of SQL Habit. 👋

SQL Habit is a course (or, as some of the students say, “business simulator”). It’s based on a story of a fictional startup called Bindle. You’ll play a role of their Data Analyst 📊 and solve real-life challenges from Business, Marketing, and Product Management.

SQL Habit course is made of bite-sized lessons (you’re looking at one atm) and exercises. They always have a real-life setting and detailed explanations. You can immediately apply everything you’ve learned at work. 🚀

“well worth the money”

Fluent in SQL in a month

Master Data Analysis with SQL with real life examples from Product Management, Marketing, Finance and more.
-- Type your query here, for example this one -- lists all records from users table: SELECT * FROM users
Loading chart... ⏳
Previous lesson: Type-casting
Next exercise: Counting books users started to read in the first week