Just got stuck in the last step of the guided project bellow (my fault, went on vacations, and spent more than a month without practicing/studying ) :
I understood the concept of the EXCEPT, what I didn’t understand is how to apply that to a single album_id Vs. a single invoice_id in order to compare a single table of the album XWZ to a single table of invoice XPTO.
So far I got here with this piece of code:
%%sql SELECT album_id, composer, track_id, name FROM track 'a' WHERE album_id = 91 EXCEPT SELECT album_id, composer, il.track_id, name FROM invoice_line 'il' INNER JOIN track 't' ON 'il'.track_id = t.track_id WHERE invoice_id = 1
But this will only ‘compare’ the album_id 91 to the invoice_id 1. How can I compare each unique album with each unique invoice?? Can anyone shed a light or give me a hint?