This advanced SQL exercise is part of the book: Advanced SQL – Practical Techniques and Use-Cases, which includes 100 day-to-day SQL challenges (and solutions), need-to-know advanced features, and key concepts.

A company that markets its products online, is using the following table to store all sales that took place in the years 2001-2002. As you can see, this table is composed of two columns – purchase date and the purchase amount.

CREATE TABLE Purchases   
(PurchaseDate varchar(25),   
 SoldAmount int)  

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