Question

我有一个包含多个列的数据集，看起来与此类似：

ID1     ID2     ID3      ID4
Blue    Grey    Fuchsia  Green
Black   Blue    Orange   Blue
Green   Green   Yellow   Pink
Pink    Yellow  NA       Orange

我想要做的是计算每个值在四列中重复的次数。例如，这就是我想从上面回来的内容：

ID      Replicates   
Blue    3       
Black   1    
Green   3       
Pink    2
Grey    1
Yellow  2
Fuchsia 1 
Orange  2

我还希望能够在频率> 2时询问数据集中存在哪个ID值。所以预期的结果将是：绿色和蓝色。

有关如何在Oracle中执行此操作的任何想法？谢谢！

Answer 1

select c, count(*)
from
(
select ID1 as c from tablename
union all
select ID2 as c from tablename
union all
select ID3 as c from tablename
union all
select ID4 as c from tablename
)
group by c

在末尾添加HAVING count(*) > 2以仅获得绿色和蓝色。

Answer 2

SELECT ID, COUNT(*) FROM(
SELECT ID1 ID FROM TBL UNION ALL
SELECT ID2 ID FROM TBL UNION ALL
SELECT ID3 ID FROM TBL UNION ALL
SELECT ID4 ID FROM TBL ) Q
GROUP BY Q.ID;

Answer 3

select id, sum(id_cnt)
(select ID1 as ID,count(*) as id_cnt from tableA group by ID1
union all
select ID2,count(*)from tableA group by ID2
union all
select ID3,count(*)from tableA group by ID3
union all
select ID4,count(*)from tableA group by ID4)
group by id

Outpout将类似于

ID      Replicates   
Blue    3       
Black   1    
Green   3       
Pink    2
Grey    1
Yellow  2
Fuchsia 1 
Orange  2

Answer 4

以下是使用Oracle unpivot关键字的另一个非常简单的选项：

select id, count(*) as replicates
from tbl
unpivot
(
  id for original_column_name in (id1, id2, id3, id4)  
)
group by id

...当然，您可以随意添加having和/或order by条款。

在不同行的多个列中查找重复值

4 个答案: