tasks/readable/017/task_readable.md

Task: 017

Database: retails

Question

Find the customer with the largest order value in each market segment.

Gold Query

WITH order_totals AS (
SELECT c_mktsegment, c.c_custkey, c.c_name, SUM(o.o_totalprice) AS total_o_totalprice
FROM customer c
JOIN orders o ON c.c_custkey = o.o_custkey
GROUP BY c_mktsegment, c.c_custkey, c.c_name
)
SELECT
ot.c_mktsegment AS market_segment,
ot.c_custkey AS customer_key,
ot.c_name AS customer_name,
ot.total_o_totalprice AS largest_value
FROM order_totals ot
JOIN (
SELECT ot2.c_mktsegment, MAX(ot2.total_o_totalprice) AS max_value
FROM order_totals ot2
GROUP BY ot2.c_mktsegment
) AS max_val ON ot.c_mktsegment = max_val.c_mktsegment AND ot.total_o_totalprice = max_val.max_value;

Execution Result:

market_segment	customer_key	customer_name	largest_value
AUTOMOBILE	114308	Customer#000114308	5486668.8
BUILDING	58421	Customer#000058421	5487155.8
FURNITURE	41290	Customer#000041290	5473361.7
HOUSEHOLD	79933	Customer#000079933	5928489.4
MACHINERY	58387	Customer#000058387	5719569.4

5 rows