Write a Stored Procedure to Count Employees in a Department
Create a Stored Procedure to Count Employees in a Department
Write a MySQL query to create a stored procedure that counts the number of employees in a specific department.
Solution:
-- Change the delimiter to allow defining a multi-line stored procedure
DELIMITER //
-- Create a stored procedure named `CountEmployeesInDepartment`
CREATE PROCEDURE CountEmployeesInDepartment(
-- Input parameter: Department ID to filter employees
IN p_DepartmentID INT,
-- Output parameter: Stores the total count of employees in the department
OUT p_EmployeeCount INT
)
BEGIN
-- Count the number of employees in the given department
SELECT COUNT(*) INTO p_EmployeeCount
FROM Employees
WHERE DepartmentID = p_DepartmentID;
END //
-- Reset the delimiter back to default `;`
DELIMITER ;
Explanation:
- Purpose of the Query:
- The goal is to automate the counting of employees in a department using a stored procedure.
- Key Components:
- SELECT COUNT(*) INTO: Counts and stores the number of employees.
- OUT: Specifies an output parameter.
- Why use Stored Procedures?:
- Stored procedures encapsulate complex queries, making them reusable.
- Real-World Application:
- For example, in a HR system, you might use a stored procedure to count employees in each department.
For more Practice: Solve these Related Problems:
- Write a MySQL query to create a stored procedure that counts the number of customers in a specific city.
- Write a MySQL query to create a stored procedure that counts the number of orders for a specific customer.
- Write a MySQL query to create a stored procedure that counts the number of products in a specific category.
- Write a MySQL query to create a stored procedure that counts the number of projects in a specific department.
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