SQL Exercise: Find employees who is working given departments
21. From the following table, write a SQL query to find the employees whose department numbers are included in 30, 40, or 90. Return employee id, first name, job id, department id.
Sample table: employees+-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+ | EMPLOYEE_ID | FIRST_NAME | LAST_NAME | EMAIL | PHONE_NUMBER | HIRE_DATE | JOB_ID | SALARY | COMMISSION_PCT | MANAGER_ID | DEPARTMENT_ID | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+ | 100 | Steven | King | SKING | 515.123.4567 | 2003-06-17 | AD_PRES | 24000.00 | 0.00 | 0 | 90 | | 101 | Neena | Kochhar | NKOCHHAR | 515.123.4568 | 2005-09-21 | AD_VP | 17000.00 | 0.00 | 100 | 90 | | 102 | Lex | De Haan | LDEHAAN | 515.123.4569 | 2001-01-13 | AD_VP | 17000.00 | 0.00 | 100 | 90 | | 103 | Alexander | Hunold | AHUNOLD | 590.423.4567 | 2006-01-03 | IT_PROG | 9000.00 | 0.00 | 102 | 60 | | 104 | Bruce | Ernst | BERNST | 590.423.4568 | 2007-05-21 | IT_PROG | 6000.00 | 0.00 | 103 | 60 | | 105 | David | Austin | DAUSTIN | 590.423.4569 | 2005-06-25 | IT_PROG | 4800.00 | 0.00 | 103 | 60 | | 106 | Valli | Pataballa | VPATABAL | 590.423.4560 | 2006-02-05 | IT_PROG | 4800.00 | 0.00 | 103 | 60 | | 107 | Diana | Lorentz | DLORENTZ | 590.423.5567 | 2007-02-07 | IT_PROG | 4200.00 | 0.00 | 103 | 60 | | 108 | Nancy | Greenberg | NGREENBE | 515.124.4569 | 2002-08-17 | FI_MGR | 12008.00 | 0.00 | 101 | 100 | | 109 | Daniel | Faviet | DFAVIET | 515.124.4169 | 2002-08-16 | FI_ACCOUNT | 9000.00 | 0.00 | 108 | 100 | ...... | 206 | William | Gietz | WGIETZ | 515.123.8181 | 2002-06-07 | AC_ACCOUNT | 8300.00 | 0.00 | 205 | 110 | +-------------+-------------+-------------+----------+--------------------+------------+------------+----------+----------------+------------+---------------+
Sample Solution:
-- Selecting 'employee_id', 'first_name', 'job_id', and 'department_id' columns from the 'employees' table
SELECT employee_id, first_name, job_id, department_id
-- Specifying the table to retrieve data from ('employees')
FROM employees
-- Filtering the results based on the condition that 'department_id' is in (30, 40, 90)
WHERE department_id IN (30, 40, 90);
Sample Output:
employee_id | first_name | job_id | department_id
-------------+------------+----------+---------------
100 | Steven | AD_PRES | 90
101 | Neena | AD_VP | 90
102 | Lex | AD_VP | 90
114 | Den | PU_MAN | 30
115 | Alexander | PU_CLERK | 30
116 | Shelli | PU_CLERK | 30
117 | Sigal | PU_CLERK | 30
118 | Guy | PU_CLERK | 30
119 | Karen | PU_CLERK | 30
203 | Susan | HR_REP | 40
(10 rows)
Code Explanation:
The said query in SQL that retrieve data from the 'employees' table and select specific columns such as "employee_id", "first_name", "job_id", and "department_id".
The rows of the result are filtered based on the value of the "department_id" column, which must be either 30, 40, or 90.
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