If you thought that we’re done with grouping and counting forever – nope, that was only the beginning The real power of this technique comes when we’re joining different tables and then grouping the records in the joined table.
Let’s look at the example of a query we wrote to check revenues per subscription. It’s time to improve it
SELECT CASE WHEN product_id = 2 THEN 'monthly' WHEN product_id = 3 THEN 'yearly' ELSE 'other_plan' END AS plan, SUM(amount) AS revenue FROM purchases WHERE refunded = FALSE GROUP BY 1
The main problem we identified...
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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.