Guided Project: Answering Business Questions using SQL, Albums vs Individual Tracks

Hello, I’m struggling to understand on how to answer the question on Screen 6 of Guided Project: Answering Business Questions using SQL

I found this solution of @shining_star8jo.

My problem is this one, if you use this code:
SELECT invoice_id, album_id FROM invoices_info GROUP BY invoice_id
And group by invoice_id without aggregation you lose around 70% of all information because it acts like DISTINCT in this case. Could someone explain me what’s the logic behind the solution? What am I supposed to compare?

Artur

Click here to view the jupyter notebook file in a new tab

I am also struggling with that

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Hi @artur.sannikov96,

I would recommend you to check out the :arrow_forward: Query Explanation part of this post:

Best,
Sahil

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