sql - 将列中的数值分别替换为列中其他值的排名

Question

假设我有一个看起来像这样的表:

+---+--------------+------+
|NUM|     NAME     |POINTS|
+-------------------------+
| 1 |   Peter      | 92   |
| 1 |   Rose       | 93   |
| 1 |   Karl       | 94   |
| 2 |   Frank      | 15   |
| 2 |   Sarah      | 16   | 
+-------------------------+

主键是 NUM 和 NAME 的组合。

现在我想用他们的排名替换 POINTS 中的数字，每个数字从 1 开始。我想实际更新表格。

示例:

+---+--------------+------+
|NUM|     NAME     |POINTS|
+-------------------------+
| 1 |   Peter      | 3    |
| 1 |   Rose       | 2    |
| 1 |   Karl       | 1    |
| 2 |   Frank      | 1    |
| 2 |   Sarah      | 2    | 
+-------------------------+

最好的方法是什么？

Answer 1

如果您想实际更改表中的值，可以使用 MERGE 语句:

merge into the_table t
using (
  select num, name, 
         dense_rank() over (partition by num order by points) as rnk
  from the_table
) x on (x.num = t.num and x.name = t.name)
when matched then update
   set points = x.rnk;

---

如果您只想显示值，请单独使用内部选择:

select num, name, 
       dense_rank() over (partition by num order by points) as points,
from the_table