Joining Tables in SQL | Dataford Interview Questions

GlobalLogic's project delivery portal stores client, project, and time-entry data separately. Write a PostgreSQL query that produces a Q2 delivery summary for every active project with a valid client.

Requirements

Join projects to clients and preserve active projects that have no qualifying time entries.
Include only time entries from April 1 through June 30, 2025, using a half-open date range.
Return total billable hours, distinct consultants, and zeroes for projects without matching entries.
Order results by project ID ascending.

Schema

clients

Column	Type	Description
client_idPK	INT	Unique client identifier
client_name	VARCHAR(100)	Client organization name
region	VARCHAR(50)	Client operating region

projects

Column	Type	Description
project_idPK	INT	Unique project identifier
client_id	INT	References clients.client_id
project_name	VARCHAR(150)	Project name
project_manager	VARCHAR(100)	Assigned project manager
status	VARCHAR(20)	Current project status

time_entries

Column	Type	Description
entry_idPK	INT	Unique time-entry identifier
project_id	INT	References projects.project_id
consultant_id	INT	Consultant who logged the entry
consultant_name	VARCHAR(100)	Consultant display name
entry_date	DATE	Date the work was performed
billable_hours	NUMERIC(6,2)	Billable hours logged

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