Patients With No Follow-Up | Dataford Interview Questions

Providence care teams need to identify patients who completed an initial visit but have not completed a follow-up visit. Write a PostgreSQL query using the tables below.

Requirements

Include only patients with at least one completed INITIAL visit.
Exclude patients who have any completed FOLLOW_UP visit.
Return each qualifying patient once, along with the date of their most recent completed initial visit.
Order the results by patient_id ascending.

A scheduled or cancelled follow-up does not count as completed. Patients with no initial visit should not appear in the results.

Schema

patients

Column	Type	Description
patient_idPK	INTEGER	Unique patient identifier
patient_name	VARCHAR(100)	Patient's display name

visits

Column	Type	Description
visit_idPK	INTEGER	Unique visit identifier
patient_id	INTEGER	References patients.patient_id
visit_type	VARCHAR(20)	Visit classification
visit_status	VARCHAR(20)	Current visit status
visit_date	DATE	Date of the visit

Your question is Patients With No Follow-Up. Start with the requirements and the two tables in the Question tab.

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