153. Deep dive into window functions. Part 1

IMO window functions are the most advanced part of SQL. It’s such a complex though powerful construct. Window functions are the last milestone on your way to become an advanced SQL user. The rest is practice, practice and more practice

Let’s take a look at the query from the last lesson. It adds numbers to users’ accounts so we can get the first account (or a signup account) of a user:

SELECT *, ROW_NUMBER() OVER (PARTITION BY user_id ORDER BY created_at ASC) AS account_number FROM accounts ORDER BY user_id ASC, created_at ASC 

ROW_NUMBER()

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