Nested Loops in SQL

Nested Loop Example in SQL

Sample Tables: Departments and Employees

DepartmentID	DepartmentName
1	HR
2	IT

EmployeeID	FirstName	LastName	DepartmentID
101	Alice	Smith	1
102	Bob	Jones	2

Nested Loop Example

We can use a nested loop to retrieve employees along with their respective department names:

SELECT Employees.EmployeeID, Employees.FirstName, Employees.LastName, Departments.DepartmentName
FROM Employees
JOIN Departments ON Employees.DepartmentID = Departments.DepartmentID;
    

Output:

EmployeeID	FirstName	LastName	DepartmentName
101	Alice	Smith	HR
102	Bob	Jones	IT

Conclusion

Nested loops in SQL allow us to combine data from multiple related tables, providing a way to retrieve meaningful information about the relationships between data.