PostgreSQL Aggregate Functions and Group By: Find the maximum salary paid to the employee working as a Programmer

4. Write a query to get the maximum salary of an employee working as a Programmer.

Sample Solution:

Code:

-- Retrieve the maximum salary among employees with the job ID 'IT_PROG'
SELECT MAX(salary) 
FROM employees 
WHERE job_id = 'IT_PROG';

Explanation:

• This SQL query is designed to retrieve the maximum (highest) salary among employees who have the job ID 'IT_PROG'.
• The MAX() function is an aggregate function in SQL that calculates the maximum value in a column.
• salary is presumably a column in the employees table that holds the salary information for each employee.
• job_id is likely a column in the employees table that identifies the job position of each employee.
• The WHERE clause filters the rows to include only those where the job_id is equal to 'IT_PROG'.
• The query calculates the maximum value in the salary column for all rows in the employees table that meet the specified condition.

Sample table: employees

Output:

pg_exercises=# SELECT MAX(salary)
pg_exercises-# FROM employees
pg_exercises-# WHERE job_id = 'IT_PROG';
   max
---------
 9000.00
(1 row)

Relational Algebra Expression:

Relational Algebra Tree:

Practice Online

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