59. Identify Volatile Admission Cost Outliers

Hard ByteDance Window Functions

Query Rules

The query columns and order must match the expected result schema.
NULL values should be handled appropriately where applicable.
The grader compares output values and sorting order to evaluate.

Schema Browser

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patients

10 cols

patient_id

INTEGER

first_name

VARCHAR(30)

last_name

VARCHAR(30)

gender

CHAR(1)

birth_date

DATE

city

VARCHAR(30)

province_id

CHAR(2)

allergies

VARCHAR(80)

height

DECIMAL(3,0)

weight

DECIMAL(4,0)

doctors

4 cols

admissions

7 cols

province_names

2 cols

Reference Solution

Expected SQL

WITH PrevNext AS (SELECT patient_id, admission_id, admission_cost, LAG(admission_cost) OVER (PARTITION BY patient_id ORDER BY admission_date) as prev_cost, LEAD(admission_cost) OVER (PARTITION BY patient_id ORDER BY admission_date) as next_cost FROM admissions) SELECT patient_id, admission_id, admission_cost FROM PrevNext WHERE prev_cost IS NOT NULL AND next_cost IS NOT NULL AND admission_cost > 1.5 * prev_cost AND admission_cost > 1.5 * next_cost;

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Console Output

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