find top 3 values with an inner join - php

Question

I have a table called users_preferred_zips that looks like this:
username | price | zip | program | active
-----------+---------+---------+-----------+---------
joe | 5 | 92108 | dog | 1
tom | 7 | 92108 | dog | 1
mary | 5 | 92108 | dog | 1
paul | 6 | 92108 | dog | 1
ron | 6 | 92108 | dog | 1
I have another table called users that looks like this
username | balance
-----------+----------
joe | 10
tom | 12
mary | 2
paul | 14
ron | 3
I need a query to pull AND sum the 3 highest values from the users_preferred_zips table where the username from the users table has a balance value greater than or equal to 5. I know i need to do some sort of inner join but my query below is not working. Here is the query i have:
SELECT SUM(price) AS SumOfTopValues
FROM (
SELECT users_preferred_zips . * , users.last_purchase, users.lesson_type, users.pref_acct_balance
INNER JOIN users ON ( users_preferred_zips.username = users.username )
WHERE users_preferred_zips.zip = '92108'
AND users_preferred_zips.program = 'dog'
AND users_preferred_zips.active = 1
AND users.pref_acct_balance >= '5'
ORDER BY price DESC
LIMIT 3
) AS sub
So the correct query would pull the following:
3 highest:
joe | 5
tom | 7
paul | 6
Sum of 3 highest values = 18
I feel like this should be pretty simple but i'm having a tough time! Thanks for your help

Answer 1

You can check this using:
SELECT SUM(price) AS SumOfTopValues
FROM users_preferred_zips
WHERE username IN (
SELECT username
FROM users
WHERE pref_acct_balance >= 5
)