73. Orphaned Reference Auditing

Hard Meta Schema Design & Optimization

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

Click a table's header to toggle expand/collapse.

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

SELECT a.admission_id, a.patient_id, a.attending_doctor_id FROM admissions a LEFT JOIN patients p ON a.patient_id = p.patient_id LEFT JOIN doctors d ON a.attending_doctor_id = d.doctor_id WHERE p.patient_id IS NULL OR d.doctor_id IS NULL;

SQL Editor

Ctrl+Enter to run

Console Output

Console Terminal

Write your query and click "Run Query" (Ctrl + Enter) to see results and testcase validation.