Active Patient Balances Sorted by Primary Provider

SELECT
  prv.provcode AS "primary provider", pt.lastname, pt.firstname, pt.id, bal.ptbalance 
FROM
  patients pt
  JOIN providers prv ON pt.providernum = prv.providernum
  JOIN PT_NONINSBALANCE bal ON pt.ptnum = bal.ptnum 
WHERE
  pt.flag = 0
  AND pt.dischargedate IS NULL
  AND pt.licnum = 101
ORDER BY "primary provider"