Oracle & MSSQL cross platform SQL

MSSQL subquery must have a alias name while Oracle does not,eg. (Note the last word 'j') SELECT MIN(actiontime) min_time FROM (SELECT CASE WHEN o.actiontime > 0 THEN o.actiontime WHEN u.actiontime > 0 THEN u.actiontime ELSE 0 END actiontime FROM relayed_emails e LEFT JOIN rm_openactions o ON e.id = o.relayed_email_id LEFT JOIN rm_urlactions u ON e.id = u.relayed_email_id WHERE e.delivery = 1 AND (o.actiontime > 0 OR u.actiontime > 0) ) j