Types of SQL Joins | Dataford Interview Questions

Explain the different types of joins in SQL and when you would use each one.

Write a PostgreSQL query that demonstrates common join types using the provided tables. Return one row for each join type and its resulting row count.

Output

Columns: join_type, row_count
Include INNER JOIN, LEFT JOIN, RIGHT JOIN, FULL OUTER JOIN, CROSS JOIN, and SELF JOIN
Return rows in that exact join-type order

Schema

employees

Column	Type	Description
employee_idPK	INTEGER	Unique employee identifier
employee_name	VARCHAR(100)	Employee full name
department_id	INTEGER	Department assigned to the employee

departments

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

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Problem