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Pattern

Aggregation

14 problemsin this pattern, climbing easy → medium → hard. Pick wherever you're calibrated.

EZ

Easy

0 / 6 solved

Count orders per customer
SQL · ~4 min
NEW
List every country we have customers in
SQL · ~3 min
NEW
Top 2 spenders by paid revenue
SQL · ~5 min
NEW
Customers with 2+ orders
SQL · ~4 min
NEW
Revenue by category
SQL · ~5 min
NEW
Daily active users
SQL · ~5 min
NEW

MD

Medium

0 / 5 solved

Orders vs unique customers per day
SQL · ~7 min
NEW
Weekday vs weekend revenue
SQL · ~7 min
NEW
Premium share of revenue
SQL · ~8 min
NEW
Average order value per customer
SQL · ~6 min
NEW
Order count and revenue by status
SQL · ~7 min
NEW

HD

Hard

0 / 3 solved

Per-customer totals without fan-out double-counting
SQL · ~15 min
NEW
Quantity-weighted average unit price
SQL · ~12 min
NEW
Categories above the average category revenue
SQL · ~12 min
NEW