mysql - This correlated subquery example seems wrong

Question

I found this example on https://sqlbolt.com/topic/subqueries

Isn't the "dept_employees" on the last row of the query should refer to a table? From the row before it shows that it is a column.

I have tried to run it on MySQL and got "Error Code: 1054. Unknown column 'dept_employees.department' in 'where clause'"

Answer 1

Perhaps it could be simplified to this but I do not know anything about MySQL.

SELECT *
FROM employees
WHERE salary >
(
    SELECT AVG(revenue_generated)
    FROM employees
    WHERE department = employees.department
)