SQL SORTING and FILTERING on HR Database: Display all the information for all employees without any department number

SQL SORTING and FILTERING on HR Database: Exercise-4 with Solution

4. From the following table, write a SQL query to find those employees who have no department number. Return employee_id, first_name, last_name, email,phone_number,hire_date, job_id, salary,commission_pct,manager_id and department_id.

Sample table: employees

Sample Solution:

SELECT *
 FROM employees
  WHERE department_id IS NULL;

Sample Output:

employee_id | first_name | last_name | email | phone_number | hire_date | job_id | salary | commission_pct | manager_id | department_id
-------------+------------+-----------+-------+--------------+-----------+--------+--------+----------------+------------+-------------
(0 rows)

Relational Algebra Expression:

Relational Algebra Tree:

Practice Online

Query Visualization:

Duration:

Rows:

Cost:

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