SQL Join Types | Dataford Interview Questions

What is the difference between an inner join, outer join, left join, and right join, and how do you use them?

Use the provided tables to demonstrate each join type. Include matched rows, unmatched rows from both sides, and the join type in the result.

Output

Columns: join_type, employee_id, employee_name, clearance_id, clearance_level
Include the rows produced by INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN
Order by join type in the sequence shown above, then employee_id, then clearance_id

employees

Column	Type	Description
employee_idPK	INT	Unique employee identifier
employee_name	VARCHAR(100)	Employee display name

clearance_records

Column	Type	Description
clearance_idPK	INT	Unique clearance record identifier
employee_id	INT	Employee associated with the clearance record
clearance_level	VARCHAR(30)	Clearance classification

Your question is SQL Join Types. Start with the requirements and the two tables in the Question tab.

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