下面是一个SQL请求:

select column_name, count(1)
from table
group by column_name
having count (column_name) > 1;

下面是一个SQL请求:

select column_name, count(1)
from table
group by column_name
having count (column_name) > 1;

我通常使用Oracle分析函数ROW_NUMBER()。

假设您想检查构建在列(c1, c2, c3)上的唯一索引或主键的副本。 然后你将这样做，打开ROW_NUMBER()带来的行数为>1的行数的ROWID s:

Select *
From Table_With_Duplicates
Where Rowid In (Select Rowid
                  From (Select ROW_NUMBER() Over (
                                 Partition By c1, c2, c3
                                 Order By c1, c2, c3
                               ) nbLines
                          From Table_With_Duplicates) t2
                 Where nbLines > 1)

1. 解决方案

select * from emp
    where rowid not in
    (select max(rowid) from emp group by empno);

我知道这是一个老帖子，但这可能会帮助一些人。

如果你需要打印表的其他列，同时检查重复使用如下:

select * from table where column_name in
(select ing.column_name from table ing group by ing.column_name having count(*) > 1)
order by column_name desc;

如果需要，还可以在where子句中添加一些额外的过滤器。

你也可以尝试这样的方法在一个表中列出所有重复的值，比如reqitem

SELECT count(poid) 
FROM poitem 
WHERE poid = 50 
AND rownum < any (SELECT count(*)  FROM poitem WHERE poid = 50) 
GROUP BY poid 
MINUS
SELECT count(poid) 
FROM poitem 
WHERE poid in (50)
GROUP BY poid 
HAVING count(poid) > 1;