oracle case when的使用和将列连接成字符串

select a.*,b.name as appname,(case a.dbsrctype when 1 then (select serverIp||':'||port||','||username||'/'||password||'@'||dbname from t_database d where d.id=a.id)  else (select url from t_webservice w where w.id=a.id)  end) as vmarkfrom t_dbsrc a left join t_appsys b on a.appid=b.id