Creating saved SQL snippets
It may feel like a lot of the SQL we've written has been copied, pasted, and reused over and over again from other queries. This is common in SQL, common in programming in general, and considered an anti-pattern. In fact, there's a principle in computing called the DRY principle, which stands for Don't Repeat Yourself (https://en.wikipedia.org/wiki/Don%27t_repeat_yourself). The principle is about how you should not rewrite the same line or lines of code again and again, as it is time-consuming and introduces more risk of bugs from typos.
Metabase has taken this principle to heart and has a feature called Saved SQL Snippets. A SQL snippet is a block of SQL that you can call upon in a single variable whenever you want to reuse it.
Throughout this chapter and book, we've been working with some iteration of the same query that takes the Orders table and flattens it out, such that every row becomes an item ordered, rather than an entire...
