Altered Table Variables chapter

Hi,

First of all, great book-thank you. I am brand new to SQL so if I have misunderstood something I apologize. 
I am working through your book using sqlite3 and ran into a problem in the table variables chapter. 
From what I understand you want to illustrate multiple instances  and you use the Movies relation. However, there is no 'rating' attribute in Movies- it only exists in Review. 
When I took this into account I had to add additional clauses to the where statement to return the correct values and remove duplicates.
If I am doing something wrong or if your phrasing works in another platform like MYSQL, maybe you could specify that in the beginning of your book. Alternatively, maybe you could change the example attribute so it only comes from one relation.
If I have totally misunderstood something, maybe you could make it clearer for SQL beginners like me.
Once again, thanks for your effort in creating this very helpful book.