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SQL exercises on employee Database: List the department where at least two employees are working

SQL employee Database: Exercise-98 with Solution

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98. From the following table, write a SQL query to find those departments where at least two employees work. Return department id, number of employees.

Sample table: employees


Sample Solution:

SELECT dep_id,
       count(*)
FROM employees
GROUP BY dep_id
HAVING count(*) >= 2;

Sample Output:

 dep_id | count
--------+-------
   3001 |     6
   1001 |     3
   2001 |     5
(3 rows)

Relational Algebra Expression:

Relational Algebra Expression: List the department where at least two employees are working.

Relational Algebra Tree:

Relational Algebra Tree: List the department where at least two employees are working.

Practice Online


Sample Database: employee

employee database structure

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Previous: 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.
Next: From the following table, write a SQL query to list the grade, number of employees, and maximum salary of each grade.

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