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

Last update on May 30 2022 07:28:40 (UTC/GMT +8 hours)

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 Tree:

Practice Online

Sample Database: employee

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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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SQL: Tips of the Day

SQL Server SELECT into existing table.

INSERT INTO dbo.TABLETWO
SELECT col1, col2
  FROM dbo.TABLEONE
 WHERE col3 LIKE @search_key

This assumes there's only two columns in dbo.TABLETWO - you need to specify the columns otherwise:

INSERT INTO dbo.TABLETWO
  (col1, col2)
SELECT col1, col2
  FROM dbo.TABLEONE
 WHERE col3 LIKE @search_key

Database: SQL Server

Ref: https://bit.ly/3y6tpA3