来自oracle的sql查询

Question

我正在使用oracle 10g EE数据库。我有一个表mytable，有两列，数据如下：

注意 ：我只想根据第二列中的相同值来查找数据，第一列中是否存在相同或不同的值并不重要。

对于A, B and C ， these 3 are required output 10重复3次， these 3 are required output

类似地20被重复2次C和D ，并且这些还需要输出

   column1             column2
--------------     ---------------

     A                  10 //required
     A                  10 //required        
     B                  10 //required
     C                  20//required
     D                  20//required
     E                  30--------not required as 30 is only here and not duplicated
     F                  40--------not required as 40 is only here and not duplicated

需要以下输出，即第二列中的值相同，第一列中的值相同或不同

   column1             column2
--------------     ---------------

     A                  10         
     A                  10           
     B                  10
     C                  20
     D                  20

Answer 1

听起来像你想要的

SELECT *
  FROM table_name t1
 WHERE column2 IN( SELECT column2
                     FROM table_name t2
                    GROUP BY column2
                   HAVING COUNT(*) > 1 )

这似乎适用于您的示例数据

SQL> with table_name as (
  2    select 'A' column1, 10 column2 from dual union all
  3    select 'A', 10 from dual union all
  4    select 'B', 10 from dual union all
  5    select 'C', 20 from dual union all
  6    select 'D', 30 from dual)
  7  SELECT *
  8    FROM table_name t1
  9   WHERE column2 IN( SELECT column2
 10                       FROM table_name t2
 11                      GROUP BY column2
 12                     HAVING COUNT(*) > 1 );

C    COLUMN2
- ----------
B         10
A         10
A         10

Answer 2

SELECT column1,
       column2
  FROM <table> t1
 WHERE column2 IN (SELECT column2
                     FROM <table> t2
                    GROUP BY column2
                    HAVING count(*) > 1);

Answer 3

从表中的第2列中选择*（通过count（*）> 1的coulmn2从表组中选择第2列）;

应该为您工作。

谢谢阿比