LDS SQL Window Functions 30 — 30 Curated SQL Problems

A 6-stage progression through ROW_NUMBER, RANK, LAG, running totals, moving averages, Top-N per partition, and NTILE bucketing — composed across 15 production-grade schemas. The pattern that separates intermediate from senior SQL candidates in onsite rounds, and the one most people can fake their way around until they can't.

Problems included in LDS SQL Window Functions 30

1. Guest Booking Sequence Number
2. Customer Order Sequence Number
3. Customer Order Sequence Number
4. Customer Charge Sequence Number
5. Number Posts per User Chronologically
6. Rank Accounts by Balance Within Account Type
7. Rank Portfolios by Value Per User
8. Rank Properties by Total Revenue
9. Rank Carriers by Shipment Volume
10. Provider Claim Rank Within Specialty
11. Order Value Change From Prior Order
12. Fare Change From Previous Trip
13. Charge Amount Change From Previous
14. Time Gap Between Consecutive Messages
15. Bill Amount Change From Previous Month
16. Cumulative Principal Paid per Loan
17. Trade Running Total Per Portfolio
18. Invoice Amount 3-Period Moving Average
19. Price Change 3-Event Moving Average
20. Campaign CTR With 7-Day Moving Avg
21. Top 2 Expensive Clicks per Campaign
22. Top Two Transactions per Customer by Amount
23. Most Expensive Listing per City
24. Top Product per Category by Revenue
25. Top Title per Genre by Rating
26. Shipment Weight Quartile Analysis
27. Listing Price Quartile Analysis
28. Organization Usage Quartile Analysis
29. User Watch Time Quartile Analysis
30. User Engagement Quartile Analysis