He wants to write departments and their average wages, in which employees currently earn over 8,000
I tried this way but it shows - 1111 - Invalid use of group function
ELECT departments.dept_name, AVG(salaries.salary) FROM departments, salaries
INNER JOIN employees ON salaries.emp_no = employees.emp_no
INNER JOIN dept_manager ON employees.emp_no = dept_manager.emp_no
INNER JOIN dept_emp ON departments.dept_no = dept_emp.emp_no
WHERE AVG(salaries.salary)>8000
And
List all employees who have the same name as employees between 1/01/0985 and 1/02/1985.
SELECT emp_no, first_name
FROM employees AS pole1
WHERE EXISTS (
SELECT pole2.emp_no
FROM employees AS pole2, salaries
WHERE pole1.first_name = pole2.first_name
AND pole1.emp_no <> pole2.emp_no
AND salaries.from_date BETWEEN 01-01-1985 AND 01-02-1985
)
This query does not want to be done
