Which join condition is missing? Explain and show how it can be found out based on the execution plan!

SELECT e.last_name, d.department_name, l.country_id, l.state_province

FROM employees e, locations l, departments d

WHERE e.department_id = d.department_id;

Question

Which join condition is missing? Explain and show how it can be found out based on the execution plan!​ 
 
SELECT e.last_name, d.department_name, l.country_id, l.state_province 
 
FROM employees e, locations l, departments d 
 
WHERE e.department_id = d.department_id;​

Answer

The one between EMPLOYEES and LOCATIONS because those are the first two tables.

Answer

The one between DEPARTMENTS and EMPLOYEES because there is no reference to the employee_id in the WHERE clause.

Answer

The one between DEPARTMENTS and LOCATIONS because those are the tables in the CARTESIAN JOIN operation.

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Which join condition is missing? Explain and show how it can be found out based ...

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