Suppliers Dominating Every Warehouse

A supplier dominates a warehouse when its available_units equal the highest available_units among all suppliers in that active warehouse; ties dominate jointly. Return suppliers that dominate every active warehouse. A missing supplier-warehouse row fails coverage. Return supplier_id ordered ascending. Return columns: supplier_id.

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Challenge overview

What you will practice

A supplier dominates a warehouse when its available_units equal the highest available_units among all suppliers in that active warehouse; ties dominate jointly. Return suppliers that dominate every active warehouse. A missing supplier-warehouse row fails coverage. Return supplier_id ordered ascending. Return columns: supplier_id.

Difficulty: Expert
SQL concept: CTE