Using max result as a value for a predicate in SQL
Yes this is possible. Your query has several syntax errors however. 


a dash in an identifier is invalid. I used an underscore instead in the below example. If you did create the columns that way, you will need to quote them, e.g. "person-name"
the equality operator in SQL is =, not ==
String constants need to be put in single quotes (') not double quotes


It is possible to use the result of the max subquery as a single values because it is a single value. To be accurate it is a subquery that because of the max() returns a single column and a single row.

select person_name
from Works
where salary &gt; (select max(salary)
                from Works
                where company_name = 'Google');


You could use an alternative way with &gt; ALL instead of &gt;, with a subquery that doesn't have an aggregate function and returns many values (many rows but still a single column):

select person_name
from Works
where salary &gt; ALL (select salary
                    from Works
                    where company_name = 'Google'
                      and salary is not null );


Note the salary is not null condition in this second query. Nulls must be taken out of the comparison because each of them would evaluate the &gt; operation to unknown rather than true or false, and as a result the whole &gt; ALL condition result would be unknown and you would get no rows in the output.