摘要： 1.交换两条记录的属性值update tx_ry ry1 set px=(select px from tx_ry where id in (pk1,pk2) and id<>ry1.id) where id in (pk1,pk2);2.自关联查询select mk.*,level from xt_xtmk mk where 1=1 start with mc='附加信息管理' connect by prior id=fid --向下查union selectmk.*,level from xt_xtmk mk where 1=1 start with mc=&# 阅读全文