select count(1) from Tt_Device_Point point full join tt_area area on point.AREA_ID in (SELECT area_id FROM Tt_Area t START WITH t.area_id = point.AREA_ID CONNECT BY t.tt__area_id = PRIOR t.area_id);需求是统计所有区域对应的设备总数
SELECT area_id FROM Tt_Area t START WITH t.area_id = point.AREA_ID CONNECT BY PRIOR t.tt__area_id = t.area_id
select area.area_id, area.area_code, area.area_name, (select count(1) from Tt_Device_Point p where p.area_id in (SELECT area_id FROM Tt_Area t START WITH t.area_id = area.AREA_ID CONNECT BY t.tt__area_id = PRIOR t.area_id)) from Tt_Area area搞定了,自己想错了,呵呵
SELECT area_id
FROM Tt_Area t
START WITH t.area_id = point.AREA_ID
CONNECT BY PRIOR t.tt__area_id = t.area_id