Problem Description –
Employees can belong to multiple departments. When the employee joins other departments, they need to decide which department is their primary department. Note that when an employee belongs to only one department, their primary column is
Write an SQL query to report all the employees with their primary department. For employees who belong to one department, report their only department.
Return the result table in any order.
The query result format is in the following example.
Problem Link – Primary Department
Difficulty Level – Easy
SELECT DISTINCT employee_id, department_id FROM ( SELECT employee_id, department_id, primary_flag, COUNT(department_id) OVER(PARTITION BY employee_id) as total_count FROM Employee ) x WHERE total_count = 1 OR primary_flag = 'Y'