Question

ColA ColB ColC ColD
  data1 rata1 T Test1
  data1 rata3 F Test2
  data1 rata2 T Test1
  data2 rata1 T Test1
  data2 rata3 T Test1
  data3 rata4 T Test1

有四列Varchar类型。我想确定的是ColB的每个唯一值（rata1，rata2等），找到ColA和其他两列（ColC，ColD）的相应值，其中ColA的特定值出现0或1次。例如 - 对于rata1，data1和data2出现一次，因此输出将包括下面显示的列以及其他不同ColB值的列。

data1    rata1    T     Test1
data2    rata1    T     Test1

如果有人可以提供任何建议，我们将非常感激。

Answer 1

我认为以下查询将实现您的目标。

With MyQuery as
(
     select ColA, ColB
       from MyTable
   group by ColA, ColB
     having count(*) <= 1
)
select ColA, ColB, ColC, ColD
  from MyTable t inner join MyQuery q on t.ColB = q.ColB and t.ColA = q.ColA

编辑以包含John C在评论中提供的修改。

With MyQuery as
(
     select ColB
       from MyTable
   group by ColB
     having count(ColA) <= 1
)
select ColA, ColB, ColC, ColD
  from MyTable t inner join MyQuery q on t.ColA = q.ColA

Answer 2

我从你那里得到的问题是你想要不同的ColB值，然后想要ColA，ColC和ColD对应于那个ColB值。如果是这种情况，您不必混淆自己，只需按ColB订购。

所以查询是

select * from TableA o left outer join
(select distinct ColA,ColB from TableA t)
 on o.ColA = t.ColA and o.ColB = t.ColB 
group by o.ColA having count(*) <= 1

Answer 3

With MyQuery as (select ColB from MyTable group by ColB having count(ColA) <= 1) select
t.ColB, ColA, ColC, ColD from MyTable t inner join MyQuery q on t.ColB = q.ColB

Oracle查询获取所需的输出

3 个答案: