tasks/readable/014/task_readable.md

Task: 014

Database: retails

Question

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

Gold Query

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)