last_positive_days.sql

SELECT
  NVL (MIN(days_since_last_positive), 0) AS days_since_last_positive
FROM (
  SELECT
    order_id,
    ROUND(trunc(sysdate) - to_date(specimen_received_datetime, 'YYYY-MM-DD"T"HH24:MI:SS'), 2) AS days_since_last_positive
  FROM
    covid.results
  WHERE
    tufts_person_id = '1295695'
    AND result_value = 'POSITIVE'
  ORDER BY
    specimen_received_datetime DESC)
WHERE
  rownum < 2;