Introduction
GROUP BY – Recap
ROLLUP
Instruction
To quickly recap what you already know about grouping rows in SQL, here is a simple problem: suppose we want to know the average score for each TV show contestant over the course of five weeks. In SQL, we'd write the following query:
SELECT full_name, AVG(score) AS avg_score FROM contest_score GROUP BY full_name;
In this simple query, we grouped the results by a single column (full_name) and used the AVG() function to calculate the average score for each contestant. Nothing really difficult.
Exercise
How much, in total, was spent on deliveries for each category? Show two columns: category and the sum of total_price (as total).
Stuck? Here's a hint!
Simply GROUP BY category.
