SQL exercises on employee Database: Display the number of employee for each job in each department
SQL employee Database: Exercise-97 with Solution
[An editor is available at the bottom of the page to write and execute the scripts.]
97. From the following table, write a SQL query to count the number of employees of each designation in each department. Return department id, job name and number of employees.
Sample table: employees
Sample Solution:
SELECT dep_id,
job_name,
count(*)
FROM employees
GROUP BY dep_id,
job_name;
Sample Output:
dep_id | job_name | count --------+-----------+------- 3001 | MANAGER | 1 2001 | ANALYST | 2 3001 | SALESMAN | 4 1001 | MANAGER | 1 1001 | PRESIDENT | 1 2001 | MANAGER | 1 2001 | CLERK | 2 1001 | CLERK | 1 3001 | CLERK | 1 (9 rows)
Relational Algebra Expression:

Relational Algebra Tree:

Practice Online
Sample Database: employee

Have another way to solve this solution? Contribute your code (and comments) through Disqus.
Previous: From the following table, write a SQL query to list the managers and number of employees work under them. Sort the result set in ascending order on manager. Return manager ID and number of employees under them.
Next: From the following table, write a SQL query to find those departments where at least two employees work. Return department id, number of employees.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
SQL: Tips of the Day
Delete all Duplicate Rows except for One in MySQL?
SELECT * FROM names; +----+--------+ | id | name | +----+--------+ | 1 | google | | 2 | yahoo | | 3 | msn | | 4 | google | | 5 | google | | 6 | yahoo | +----+--------+
1. If you want to keep the row with the lowest id value:
DELETE n1 FROM names n1, names n2 WHERE n1.id > n2.id AND n1.name = n2.name
2. If you want to keep the row with the highest id value:
DELETE n1 FROM names n1, names n2 WHERE n1.id < n2.id AND n1.name = n2.name
Ref: https://bit.ly/3NroM8o
- New Content published on w3resource:
- HTML-CSS Practical: Exercises, Practice, Solution
- Java Regular Expression: Exercises, Practice, Solution
- Scala Programming Exercises, Practice, Solution
- Python Itertools exercises
- Python Numpy exercises
- Python GeoPy Package exercises
- Python Pandas exercises
- Python nltk exercises
- Python BeautifulSoup exercises
- Form Template
- Composer - PHP Package Manager
- PHPUnit - PHP Testing
- Laravel - PHP Framework
- Angular - JavaScript Framework
- Vue - JavaScript Framework
- Jest - JavaScript Testing Framework