Data explorer challenge: Generate list of members by location

Data & reporting
6

Maybe I don’t understand the question but, if I do, then

SELECT u.username
    FROM users u
    LEFT JOIN user_profiles up ON u.id = up.user_id
    WHERE location = 'Pakistan'

or, equally,

SELECT username from user_profiles, users 
where user_id = id and location = 'Pakistan'

Note that the Data Explorer does not accept double quotes as delimiters.