小菜之道

摘要： 表demo是重复拷贝自dba_objects，有88万左右，不重复的是27323，没有索引方法一：delete from demo a where a.rowid <> (select max(rowid) from demo b whereb.object_id=a.object_id);耗时：几个小时以上方法二： delete from demo where rowid in(select rid from(select rowid rid,row_number() over(partition by object_id order by rowid) rnfrom demo) 阅读全文