Practice / window functions
A retail chain wants each store's single best-selling product.
product_sales
Your task: return store, product, and units for the best-selling product in each store (the highest units). If two products in a store tie on units, keep the one whose product name comes first alphabetically — so every store returns exactly one row.
Assign your answer DataFrame to result. Row order doesn't matter.
product_salesinput DataFrame| column | type |
|---|---|
| store | string |
| product | string |
| units | long |
| store | product | units |
|---|---|---|
| Downtown | Pen | 40 |
| Downtown | Ink | 55 |
| Pier | Pen | 20 |
| Pier | Pad | 35 |
| Uptown | Mug | 30 |
| Uptown | Cup | 30 |
storeproductunits· 3 rowsWindow.partitionBy("store").orderBy(F.col("units").desc(), F.col("product").asc()),
then F.row_number().over(w) == 1. The product tiebreaker keeps exactly one
row per store when two products sell the same number of units.
This problem builds on Window Functions (~9 min). Pop it open in a new tab if you want a quick recap.