26. Same-Allergy Geographic Co-location

Medium Uber Joins (All Types)

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

SELECT p1.first_name as p1_first, p2.first_name as p2_first, p1.city, p1.allergies FROM patients p1 JOIN patients p2 ON p1.city = p2.city AND p1.allergies = p2.allergies AND p1.patient_id < p2.patient_id WHERE p1.allergies IS NOT NULL;

SQL Editor

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Console Output

Console Terminal

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