Bindle made a new feature – now users can buy real printed books. They rolled it out for US users and asked users for their addresses.
Turned out, they forgot to add a client-side validation (so users can’t submit invalid data) and users typed incorrect postal codes (so there’s no way books will be delivered).
Well, sometimes things like this happen. Since some data in our database is polluted we need to clean it up (ideally remove invalid postal codes completely and turn on the validation to make it future proof).
Great news: US postal codes...
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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. 