请问怎么在一个数据集里进行跨库查询啊 select * from (select hdr.TAG_VALUE from hme_data_record hdr,--分库 MT_TAG_B mtb,--主库 HME_EQUIPMENT_WORKCELL_REL mewr,--主库 hme_equipment he--主库 where mtb.tag_code='YZTCPLSJJBZSTCJBJ' and mtb.tag_id=hdr.tag_id and he.equip_num='3030AN11ZBJB001' and he.equipment_id=mewr.equipment_id and hdr.workcell_id=mewr.workcell_id order by hdr.record_date desc ) where rownum<2 用的是Oracle数据库 |