1789. Primary Department for Each Employee LeetCode Solution

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Problem Statement
Complexity Analysis
Primary Department for Each Employee solution in C++
Primary Department for Each Employee solution in Java
Primary Department for Each Employee solution in Python
Additional Resources

1789. Primary Department for Each Employee LeetCode Solution image

Problem Statement of Primary Department for Each Employee

Table: Employee

+—————+———+
| Column Name | Type |
+—————+———+
| employee_id | int |
| department_id | int |
| primary_flag | varchar |
+—————+———+
(employee_id, department_id) is the primary key (combination of columns with unique values) for this table.
employee_id is the id of the employee.
department_id is the id of the department to which the employee belongs.
primary_flag is an ENUM (category) of type (‘Y’, ‘N’). If the flag is ‘Y’, the department is the primary department for the employee. If the flag is ‘N’, the department is not the primary.

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 ‘N’.
Write a solution 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 result format is in the following example.

Example not found

Constraints not found

Complexity Analysis

Time Complexity: Google AdSense
Space Complexity: Google Analytics

1789. Primary Department for Each Employee LeetCode Solution in C++

SELECT
  employee_id,
  department_id
FROM Employee
WHERE primary_flag = 'Y'
UNION DISTINCT
SELECT
  employee_id,
  department_id
FROM Employee
GROUP BY 1
HAVING COUNT(*) = 1;
/* code provided by PROGIEZ */