Code Review, please! ("challenge:each country's best customer")

Hey guys, below is a screenshot of my solution to the challenge "each country’s best customer’ under “Building and Organizing Complex Queries.” Quite different from the solution suggested by DQ but it worked! I prefer the way I solved it since is much shorter but I’m new to coding so I’m just hoping for feedback on it. Thanks!

Screen link: Learn data science with Python and R projects

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Hi!

On my first attempt to solve this challenge I had a similar query, but then I looked through other threads on this mission and realized why my solution was not correct although giving the same results.

In short, the answer would be: you can´t leave any non-aggregated column outside the GROUP BY clause.

For more explanation, please, check this great step-by-step explanation of why it is important to include all the non-aggregated columns inside the GROUP BY and a couple of other threads with similar questions:

  1. Solution for 190-8 "Challenge: Each Country's Best Customer" seems overly complicated? - #2 by Bruno
  2. 190-8 Feedback - Building and Organizing Complex Queries - Challenge
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Thank you, Ksenia.

The oldest of these answers was eventually turned into this blog post.

Great! Everything is gathered together in one place :+1:t2:
It would have saved me some time if I had seen it when was struggling with this challenge :slight_smile:

Absolutely truth, Cause why would Dataquest teach as the most simplest technique but end up recommending an answer which is contrary to the simplicity they have been expecting from us.