SQL for Top Readmissions | Dataford Interview Questions

Given a dataset, write a SQL query to find the top 10 patients with the highest readmission rates.

For this exercise, a readmission is an admission occurring within 30 days after a patient's discharge. Calculate each patient's readmission rate as readmissions divided by completed admissions.

Output

One row per patient with at least one completed admission.
Columns: patient_id, patient_name, total_admissions, readmissions, and readmission_rate.
Sort by readmission rate descending, then readmission count descending, then patient ID ascending. Return at most 10 rows.

Schema

patients

Column	Type	Description
patient_idPK	INT	Unique patient identifier
patient_name	VARCHAR(100)	Patient display name

hospital_admissions

Column	Type	Description
admission_idPK	INT	Unique admission identifier
patient_id	INT	Patient associated with the admission
admission_date	DATE	Date the patient was admitted
discharge_date	DATE	Date the patient was discharged

Your question is SQL for Top Readmissions. Start with the requirements and the two tables in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem