This query demonstrates the use of a subquery to create values in a column — nextreviewdate, in this case. Adjust the date range as needed.
SELECT
(DATE(COALESCE(
(SELECT MIN(nextreviewdate)
FROM sos.v_tpreviews
WHERE ptepisodenum = b.ptepisodenum
AND tpheadernum = c.tpheadernum
AND spv_signandfinalize = 1
AND rowstatus = 'O' ),c.nextreviewdate)
)) AS nextreviewdate,
(a.lastname+', '+a.firstname+' / '+a.id) AS "Patient",
d.provcode AS "Primary Provider"
FROM
sos.patients a
JOIN sos.ptepisodes b ON a.ptnum = b.ptnum
JOIN sos.tpheaders c ON b.ptepisodenum = c.ptepisodenum
LEFT OUTER JOIN sos.providers d ON b.providernum = d.providernum
WHERE
a.flag = 0
AND b.currentflag = 1
AND a.dischargedate IS NULL
AND nextreviewdate BETWEEN '2009-09-01' AND '2009-09-30'
ORDER BY "NextReviewDate","Patient"
