text: --Queries
  --List the following details of each employee: employee number, last name, first name, sex, and salary.
  SELECT employees.emp_no, employees.last_name, employees.first_name, employees.sex,salaries.salary
  FROM employees
  INNER JOIN salaries ON
  salaries.emp_no = employees.emp_no; 
  
  --List first name, last name, and hire date for employees who were hired in 1986.
  SELECT first_name, last_name, hire_date
  FROM employees
  WHERE extract(year from hire_date) = 1986
  
  --List the manager of each department with the following information: department number, department name, the manager's employee number, last name, first name.
  SELECT dept_manager.dept_no, departments.dept_name, dept_manager.emp_no, employees.last_name, employees.first_name 
  FROM dept_manager
  INNER JOIN departments ON
  departments.dept_no = dept_manager.dept_no
  INNER JOIN employees ON
  employees.emp_no = dept_manager.emp_no;
  
  --List the department of each employee with the following information: employee number, last name, first name, and department name.
  SELECT dept_emp.emp_no, employees.last_name, employees.first_name, departments.dept_name 
  FROM dept_emp
  INNER JOIN employees ON
  employees.emp_no = dept_emp.emp_no
  INNER JOIN departments ON
  departments.dept_no = dept_emp.dept_no;
  
  --List first name, last name, and sex for employees whose first name is "Hercules" and last names begin with "B."
  SELECT first_name, last_name, sex
  FROM employees
  WHERE first_name = 'Hercules'
  AND last_name LIKE 'B%';
  
  --List all employees in the Sales department, including their employee number, last name, first name, and department name.
  SELECT employees.emp_no, employees.last_name, employees.first_name, departments.dept_name
  FROM employees
  INNER JOIN dept_emp ON
  dept_emp.emp_no = employees.emp_no
  INNER JOIN departments ON
  departments.dept_no = dept_emp.dept_no
  WHERE departments.dept_name = 'Sales';
  
  --List all employees in the Sales and Development departments, including their employee number, last name, first name, and department name.
  SELECT employees.emp_no, employees.last_name, employees.first_name, departments.dept_name
  FROM employees
  INNER JOIN dept_emp ON
  dept_emp.emp_no = employees.emp_no
  INNER JOIN departments ON
  departments.dept_no = dept_emp.dept_no
  WHERE departments.dept_name = 'Sales' 
  OR departments.dept_name = 'Development';
  
  --In descending order, list the frequency count of employee last names, i.e., how many employees share each last name.
  SELECT last_name, COUNT(last_name) AS "Last Name Count"
  FROM employees
  GROUP BY last_name
  Order By "Last Name Count" DESC ;
  
  
  
  
  
  