Question

我有一个类似下面的表格。现在，我想获取第2列中具有最大价值的第1列元素的每个组名称的2条记录。例如，对A取85和75，对B取65和45 ... 我使用oracle数据库。 TNX

 ----------------------
 |Column 1 | Column 2 |
 ----------------------
 |    A    |    85    |
 ----------------------
 |    A    |    75    |
 ---------------------
 |    A    |    60    |
 ---------------------
 |    A    |    50    |
 ---------------------
 |    B    |    65    |
 ---------------------
 |    B    |    45    |
 ---------------------
 |    B    |    35    |
 ---------------------
 |    B    |    25    |
 ---------------------

Answer 1

尝试使用row_number（）

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Answer 2

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row_number

Answer 3

您可以使用row_number()：

select t.*
from (select t.*,
             row_number() over (partition by col1 order by col2 desc) as seq 
      from table t
     ) t
where seq <= 2;

但是，fetch first . . .子句也有帮助：

select t.*
from table t
where t.col2 in (select t1.col2
                 from table t1
                 where t1.col1 = t.col1
                 order by t1.col2 desc
                 fetch first 2 rows only
                );

Answer 4

尝试一下

这里是演示solution

SQL

select col1,col2 from (select col1,col2, rank() over(partition by col1 order by col2 desc) as rn from t) q where q.rn<=2;

为第2列中值最大的第1列元素的每个组名称获取2条记录

4 个答案: