Question

我有一张表有两个列，id和日期。这是相同的样本数据。

ID          DATE
1           01-Jan -14 05.42.23.000000000 pm
1           01-Jan -14 05.06.17.000000000 pm
2           01-Jan -14 05.26.16.000000000 pm
2           01-Jan -14 05.41.20.000000000 pm
3           01-Jan -14 05.21.19.000000000 pm
3           01-Jan -14 05.08.18.000000000 pm
4           01-Jan -14 05.14.17.000000000 pm
4           01-Jan -14 05.17.17.000000000 pm

列ID包含需要删除的重复数据，我想保留列DATE更大的行。

我写SQL但结果不正确。

delete from newproducts a
 where a.id in
       (select t.id from newproducts t group by t.id having count(*) > 1)
   and a.date not in
       (select max(t.date) from newproducts  t group by t.id having count(*) > 1);

如何纠正？感谢

Answer 1

这适用于sql server;

delete a from newproducts as a
 where 
exists(
select * from newproducts b
where a.id = b.id and a.date < b.date)

相同或以下应该适用于oracle;

delete from newproducts a
 where 
exists(
select * from newproducts b
where a.id = b.id and a.date < b.date)

Answer 2

尝试使用exists子查询：

delete from newproducts np
    where not exists (select 1
                      from newproducts np2
                      where np2.id = np.id and np2.date > np.date
                     );

删除oracle中的重复记录

2 个答案: