This query delivers a list of discharged patients with rendering provider and discharge date. If the patient was seen by more than one provider, he or she will appear multiple times in the list:
SELECT
DISTINCT pt.lastname, pt.firstname, pt.id, pr.provcode, pt.dischargedate
FROM
sos.providers pr
JOIN sos.jcharges jc ON jc.providernum = pr.providernum
JOIN sos.patients pt ON jc.ptnum = pt.ptnum
WHERE
pt.dischargedate IS NOT NULL
ORDER BY
pt.lastname, pt.firstname, pt.id, pr.provcode
To sort by provider, rather than patient name, just change the ORDER BY clause:
SELECT
DISTINCT pt.lastname, pt.firstname, pt.id, pr.provcode, pt.dischargedate
FROM
sos.providers pr
JOIN sos.jcharges jc ON jc.providernum = pr.providernum
JOIN sos.patients pt ON jc.ptnum = pt.ptnum
WHERE
pt.dischargedate IS NOT NULL
ORDER BY
pr.provcode, pt.lastname, pt.firstname, pt.id