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This problem is labeled as Intermediate. 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.

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Practice SQL Window Functions | Xorthax's Trading Post

Tables Used

orders

Column	Type
orderid	bigint
customerid	bigint
orderdate	timestamp without time zone
totalamount	double precision
status	text

Expected Output

Column
customerid
orderid
orderdate
totalamount

22. Clone Order Detector

Identify duplicate orders by customer, date, and total ... and assign row numbers.

Xorthax suspects duplicate orders. Write a query to identify all duplicate orders for the same customer with the same total amount and order date. Assign a unique row number to each duplicate.

Write Your Query

This problem is labeled as Intermediate. 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)

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