如何删除一个表里面的重复行

delete from table_name where rowid not in (select max(rowid) from table_name group by duplicate_values_field_name);
或者
delete duplicate_values_field_name dv from table_name ta where rowid <(select min(rowid) from table_name tb where ta.dv=tb.dv);
或者
DELETE FROM table_name A WHERE rowid>(SELECT MIN(rowid) FROM table_name B WHERE A>key_values=B.key_values);