Handling NULLs with COALESCE

Problem

You are generating an organization chart CSV file, but the software crashes when it hits a NULL manager_id for the CEO. Retrieve first_name and manager_id, but if manager_id is NULL, return the string "CEO" instead.

Database Schema

Table: employees

• employee_id (INT): Unique identifier for the employee.
• first_name (VARCHAR): First name of the employee.
• last_name (VARCHAR): Last name of the employee.
• salary (INT): Employee's salary.
• department_id (INT): Foreign key referencing the department.
• manager_id (INT): Foreign key referencing the manager (another employee).
• hire_date (DATE): Date the employee was hired.

Table: departments

• department_id (INT): Unique identifier for the department.
• department_name (VARCHAR): Name of the department.

Try It

Hint

Solution