SQL Joins Explanation | Dataford Interview Questions

Explain the joins in SQL.

Using the provided tables, write a query that demonstrates the required join behavior by reporting every department, including departments without employees or active assignments. Include only active project assignments in the project count.

Output

One row per department with department_name, employee_count, and active_project_count
Include all departments, including those with zero employees or active projects
Order by department_id ascending

Schema

departments

Column	Type	Description
department_idPK	INT	Unique department identifier
department_name	VARCHAR(100)	Department name

employees

Column	Type	Description
employee_idPK	INT	Unique employee identifier
employee_name	VARCHAR(100)	Employee full name
department_id	INT	Employee department identifier

project_assignments

Column	Type	Description
assignment_idPK	INT	Unique assignment identifier
employee_id	INT	Assigned employee identifier
project_id	INT	Project identifier
assignment_status	VARCHAR(20)	Assignment status

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