PostgreSQL Subquery: Find the name and salary of the employees who draws the same salary as the minimum salary for all departments

9. Write a SQL subquery to find all the information of the employees who draws the same salary as the minimum salary for all departments.

Sample Solution:

Code:

-- This SQL query retrieves all columns of the employee(s) with the minimum salary in the employees table.

SELECT * -- Selects all columns from the employees table
FROM employees -- Specifies the table from which to retrieve data, in this case, the employees table
WHERE salary = ( -- Filters the rows to include only those where the salary matches the minimum salary obtained from the subquery
    SELECT MIN(salary) -- Subquery: Calculates the minimum salary among all employees
    FROM employees
);

Explanation:

• This SQL query retrieves all columns of the employee(s) with the minimum salary in the employees table.
• The outermost SELECT statement selects all columns from the employees table.
• The WHERE clause filters the rows to include only those where the salary matches the minimum salary obtained from the subquery.
• The subquery calculates the minimum salary among all employees using the MIN() function.

Sample table: employees

Sample table: departments

Output:

pg_exercises=# SELECT *
pg_exercises-# FROM employees
pg_exercises-# WHERE salary = (
pg_exercises(# SELECT MIN(salary)
pg_exercises(# FROM employees);

 employee_id | first_name | last_name |     email     | phone_number | hire_date  |  job_id  | salary  | commission_pct | manager_id | department_id
-------------+------------+-----------+---------------+--------------+------------+----------+---------+----------------+------------+---------------
         132 | TJ         | Olson     | not available | 650.123.8234 | 1987-07-19 | ST_CLERK | 2100.00 |           0.00 |        121 |            50
(1 row)

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