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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
streakstart
streakend
streaklength

76. Unbroken Chains of Loyalty

Amid the constellations of commerce, only a few customers blaze with streaks unbroken across the passing months.

Xorthax wants to find the single longest streak of consecutive months where each customer placed at least one order. Show the the first day of the start month as a date, the first day of the end month as a date, and streak length for each customer, ordered by the highest streaks first.

Write Your Query

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.

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