Do I need advanced SQL to attempt this?

This problem is labeled as Advanced. You don’t need to be an expert, only comfortable with SQL and willing to experiment. If you get stuck, the hints and solution will help you along.

Will I get hints and step-by-step explanations if I get stuck?

Yes. Every problem comes with optional hints you can reveal one at a time, plus a fully worked step-by-step solution. Hints and solutions will link to Learning Pages where you can get more information about particular concepts. You decide how much help you want while practicing.

Tables Used

orderdetails

Column	Type
orderdetailid	bigint
orderid	bigint
productid	bigint
quantity	bigint
unitprice	double precision
currencyid	bigint

products

Column	Type
productid	bigint
name	text
description	text
category	text
price	double precision
supplierid	bigint
stockquantity	bigint

suppliers

Column	Type
supplierid	bigint
name	text
originplanet	text
contactinfo	text
rating	double precision

Expected Output

Column
category
productname
totalsales
salesrank
runningsales

Running Sales by Category: Rank Products by Sales Volume and Calculate Running Totals Within Each Category

Rank products by total quantity sold and compute the running sales total per category.

The merchants guild wants to analyze the popularity of products by category. Write a query to rank products by total quantity sold and calculate the running sum of sales for each product category.

Write Your Query

This simulates analyzing category-level sales performance to identify top-selling products and monitor cumulative sales growth.

You'll practice combining ranking and running aggregation techniques to track performance and cumulative trends within grouped data.

This problem is labeled as Advanced. You don’t need to be an expert—just comfortable with SQL and willing to experiment. If you get stuck, the hints and solution will guide you step by step.

Yes. Every problem comes with optional hints you can reveal one at a time, plus a fully worked step-by-step solution. You decide how much help you want while practicing.

All problems on PracticeWindowFunctions.com are completely free and can be solved without creating an account. Right now there are over 80 practice problems, with new ones added regularly.

SQL Cookbook (O’Reilly)

Practical SQL recipes for real-world querying—great complement to hands-on practice.

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