PostgreSQL Aggregate Functions and Group By: Find the number of jobs available in the employees table

1. Write a query to find the number of jobs available in the employees table.

Sample Solution:

Code:

SELECT COUNT(DISTINCT job_id) 
FROM employees;

Sample table: employees

Output:

pg_exercises=# SELECT COUNT(DISTINCT job_id)
pg_exercises-# FROM employees;
 count
-------
    19
(1 row)

Relational Algebra Expression:

Relational Algebra Tree:

Practice Online

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