I will speak about the technical first step where I needed solving questions in Python (half an hour) and in Sql(half an hour).
I succeeded solving 2 SQL questions and 1 in Python.
Sql Part:
I was given 5 tables presented a library. But the main 2 and only tables I needed to use in the following questions were: copies and checkouts.
copies table : book_id,copy_id,condition.
checkouts table: copy_id,checkout_date,returned_date,renwed_count.
First Q:
Calculate the total number of books their condition is good and havent returned yet (it should be called "numbers_of_returned_books"). Take this total and return the books' precentage that their renewed > 2 (this should be called "pct_renewed").
The output should be - numbers_of_returned_books and pct_renewed.
Second Q:
They defined a value - lifetime_value. This value is calculated as : numbers of days since the day they were taken and returned. I was asked to bring the book ids their lifetime_value in top 3 books and pay attention their number of copies <=10 and their returned_Date is not null.
Python Part:
You are given a books list which cotains tuples. Each book in books list contains the book name and its score. For example:
list books = [("Agr",3),("bsa",2),("Agr",4),("mas",7)]
You need to return the highest score sum were given to the top 3 books in the list. You are not allowed sum the score number for a book twice.