Regional Support Leaders

SQL practice question · Hard · Window Functions · UnitedHealth

members has one row per patient (patient_id, region) and service_contacts has one row per support call (call_id, patient_id). Count each member's calls (0 if none; calls from patients not in members are ignored) and return, for each region, the member or members with the highest call count. Output columns: region, patient_id, call_count. Order by region, then patient_id.

Table: members

Schema of members
Column	Type
patient_id	INTEGER
region	TEXT

Schema of members

Column

Type

patient_id

INTEGER

region

TEXT

Sample rows of members
patient_id	region
101	East
102	East
103	West
104	West

Sample rows of members

patient_id

region

101

East

102

East

103

West

104

West

Table: service_contacts

Schema of service_contacts
Column	Type
call_id	INTEGER
patient_id	INTEGER

Schema of service_contacts

Column

Type

call_id

INTEGER

patient_id

INTEGER

Sample rows of service_contacts
call_id	patient_id
1	101
2	101
3	102
4	103
5	103
6	103
7	104

Sample rows of service_contacts

call_id

patient_id

101

102

103

104

Expected output on the sample data
region	patient_id	call_count
East	101	2
West	103	3

Expected output on the sample data

region

patient_id

call_count

East

101

West

103

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