oracle如何去除重复数据

create table nayi224_180824(col_1 varchar2(10), col_2 varchar2(10), col_3 varchar2(10)); insert into nayi224_180824select 1, 2, 3 from dual union allselect 1, 2, 3 from dual union allselect 5, 2, 3 from dual union allselect 10, 20, 30 from dual ;commit;select*from nayi224_180824;

select distinct t1.* from nayi224_180824 t1;

select distinct t1.col_2, col_3 from nayi224_180824 t1

select * from (select t1.*, row_number() over(partition by t1.col_2, t1.col_3 order by 1) rn from nayi224_180824 t1) t1 where t1.rn = 1;

select * from nayi224_180824 t where (t.col_2, t.col_3) in (select t1.col_2, t1.col_3 from nayi224_180824 t1 group by t1.col_2, t1.col_3 having count(1) > 1)

select * from (select t1.*, count(1) over(partition by t1.col_2, t1.col_3) rn from nayi224_180824 t1) t1 where t1.rn > 1;

delete from nayi224_180824 t where t.rowid in ( select rid from (select t1.rowid rid, count(1) over(partition by t1.col_2, t1.col_3) rn from nayi224_180824 t1) t1 where t1.rn > 1);

delete from nayi224_180824 t where t.rowid in (select rid from (select t1.rowid rid, row_number() over(partition by t1.col_2, t1.col_3 order by 1) rn from nayi224_180824 t1) t1 where t1.rn > 1);

delete from nayi224_180824 t where t.rowid not in (select max(rowid) from nayi224_180824 t1 group by t1.col_2, t1.col_3);