Tables: department, dept_emp, dept_manager, employees, salaries, titles department (columns): dept_no, dept_name dept_emp (columns): emp_no, dept_no, from_date, to_date dept_manager (columns): emp_no,...

Extracted text: Tables: department, dept_emp, dept_manager, employees, salaries, titles department (columns): dept_no, dept_name dept_emp (columns): emp_no, dept_no, from_date, to_date dept_manager (columns): emp_no, dept_no, from_date, to_date employees (columns): emp_no, birth_date, first_name, Last_name, gender, hire_date salaries (columns): emp_no, salary, from_date, to_date titles (columns): emp_no, title, from_date, to_date a) Your task is to write a SQL query to find count of employee who does not have a manager in the above given table schema?