PostgreSQL JOINS: Make a join with two tables job_history and employees to display the status of employees who is currently drawing the salary above 10000

12. Write a query to make a join with two tables job_history and employees to display the status of employees who is currently drawing the salary above 10000.

Sample Solution:

Code:

-- This SQL query retrieves job history records for employees whose salary is greater than 10000, by joining the job_history and employees tables.

SELECT jh.* -- Selects all columns from the job_history table
FROM job_history jh -- Specifies the first table from which to retrieve data, in this case, the job_history table, aliasing it as 'jh'
JOIN employees em -- Joins the job_history table with the employees table, specifying the second table and aliasing it as 'em'
ON (jh.employee_id = em.employee_id) -- Specifies the join condition based on the employee_id column
WHERE em.salary > 10000; -- Filters the rows to include only those where the salary of the employee is greater than 10000

Explanation:

• This SQL query retrieves job history records for employees whose salary is greater than 10000 by joining the job_history and employees tables.
• The SELECT statement selects all columns from the job_history table.
• The FROM clause specifies the first table from which to retrieve data, which is the job_history table, aliased as 'jh'.
• A JOIN operation is performed with the employees table, specifying the second table and aliasing it as 'em'.
• The ON clause specifies the join condition where the employee_id in the job_history table matches the employee_id in the employees table.
• The WHERE clause filters the rows to include only those where the salary of the employee is greater than 10000.

Sample table: employees

Sample table: Job_history

Output:

pg_exercises=# SELECT jh.* FROM job_history jh
pg_exercises-# JOIN employees em
pg_exercises-# ON (jh.employee_id = em.employee_id)
pg_exercises-# WHERE em.salary > 10000;
 employee_id | start_date |  end_date  |   job_id   | department_id
-------------+------------+------------+------------+---------------
         114 | 1998-03-24 | 1999-12-31 | ST_CLERK   |            50
         101 | 1993-10-28 | 1997-03-15 | AC_MGR     |           110
         101 | 1989-09-21 | 1993-10-27 | AC_ACCOUNT |           110
         102 | 1993-01-13 | 1998-07-24 | IT_PROG    |            60
         201 | 1996-02-17 | 1999-12-19 | MK_REP     |            20
(5 rows)

Practice Online

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Previous: Write a query to make a join with two tables employees and jobs to display the job title, employee name, and the difference between salary and the minimum salary of the employees.
Next: Write a query to make a join with two tables employees and departments to display department name, first_name and last_name, hire date and salary for all the managers who achieved a working experience is more than 15 years.