SQL Comma-Separated State and City | Dataford Interview Questions

Your question is SQL Comma-Separated State and City. Start with the requirements and the two tables on the right.

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Problem

Exela Technologies uses service locations to support workflows managed through Exela Process Automation. Write a PostgreSQL query that returns each eligible location's state and city as one comma-separated value.

Requirements

Join service_locations to client_accounts using client_id.
Return only locations belonging to accounts with an Active status.
Create a column named state_city in the format State, City using PostgreSQL-compatible string handling. If either component is NULL, do not add an unnecessary comma.
Return results ordered by location_id ascending.

Schema

service_locations

Column	Type	Description
location_idPK	INT	Unique service location identifier
client_id	INT	References the associated client account
city	VARCHAR(100)	City where the service location operates
state	VARCHAR(100)	State or region where the service location operates

client_accounts

Column	Type	Description
client_idPK	INT	Unique client account identifier
account_name	VARCHAR(150)	Client account name
account_status	VARCHAR(20)	Current account status