# Task: 014

**Database:** retails  

## Question
Show the supplier that supplies the most parts in their inventory in each region.


## Gold Query

```sql
WITH supplier_part_count AS (
SELECT r.r_regionkey AS region_key,
r.r_name AS region_name,
s.s_suppkey,
s.s_name,
COUNT(DISTINCT ps.ps_partkey) AS total_quantity,
RANK() OVER (PARTITION BY r.r_regionkey ORDER BY COUNT(DISTINCT ps.ps_partkey) DESC) AS rn
FROM supplier s
JOIN nation n ON s.s_nationkey = n.n_nationkey
JOIN region r ON n.n_regionkey = r.r_regionkey
JOIN partsupp ps ON s.s_suppkey = ps.ps_suppkey
GROUP BY r.r_regionkey, r.r_name, s.s_suppkey, s.s_name
)
SELECT region_key, region_name, s_suppkey, s_name, total_quantity
FROM supplier_part_count
WHERE rn = 1;
```

**Execution Result:**

| region_key   | region_name   | s_suppkey   | s_name             | total_quantity   |
|--------------|---------------|-------------|--------------------|------------------|
| 0            | AFRICA        | 2           | Supplier#000000002 | 80               |
| 0            | AFRICA        | 7           | Supplier#000000007 | 80               |
| 0            | AFRICA        | 8           | Supplier#000000008 | 80               |
| 0            | AFRICA        | 21          | Supplier#000000021 | 80               |
| 0            | AFRICA        | 22          | Supplier#000000022 | 80               |
| 0            | AFRICA        | 23          | Supplier#000000023 | 80               |
| 0            | AFRICA        | 30          | Supplier#000000030 | 80               |
| 0            | AFRICA        | 37          | Supplier#000000037 | 80               |
| 0            | AFRICA        | 39          | Supplier#000000039 | 80               |
| 0            | AFRICA        | 41          | Supplier#000000041 | 80               |
| ...          | ...           | ...         | ...                | ...              |
| 4            | MIDDLE EAST   | 9965        | Supplier#000009965 | 80               |
| 4            | MIDDLE EAST   | 9966        | Supplier#000009966 | 80               |
| 4            | MIDDLE EAST   | 9967        | Supplier#000009967 | 80               |
| 4            | MIDDLE EAST   | 9969        | Supplier#000009969 | 80               |
| 4            | MIDDLE EAST   | 9985        | Supplier#000009985 | 80               |
| 4            | MIDDLE EAST   | 9989        | Supplier#000009989 | 80               |
| 4            | MIDDLE EAST   | 9991        | Supplier#000009991 | 80               |
| 4            | MIDDLE EAST   | 9992        | Supplier#000009992 | 80               |
| 4            | MIDDLE EAST   | 9994        | Supplier#000009994 | 80               |
| 4            | MIDDLE EAST   | 9996        | Supplier#000009996 | 80               |

*... truncated (10000 rows total)*