PostgreSQL-重新编号列 [英] Postgresql - Renumber columns

问题描述

我需要重新编号数据库的行。删除某些行后，我必须重新编号某些列。如何使用 postgresql 做到这一点？

I need to renumber the rows of my database. After I delete some rows I have to renumber certain column. How can I do that using postgresql?

更新：
例如：
我有一个这样的表：

UPDATE: For example: I have a table like this:

ac_n_circ     name

1               x 
2               y
8               c
15              b

我想像这样对表重新编号：

And I want to renumber this table like this:

ac_n_circ     name

1               x 
2               y
3               c
4               b

是否有任何算法或类似方法可以执行此操作

Is there any algorithm or something like that to do this in posgresql?

谢谢！

推荐答案

警告：

仅当 ac_n_circ 不是主键列时才有意义。

如果您确定需要这个（真的吗？），则应执行以下操作：

Caution:

This only makes sense if ac_n_circ is NOT the primary key column.

If you are sure you need this (are you really?), then something like the following should work:

with new_numbers as  (
   select row_number() over (order by ac_n_circ) as new_nr,
          ac_n_circ, 
          id
   from foo
) 
update foo
   set ac_n_circ = nn.new_nr
from new_numbers nn 
 where nn.id = foo.id;

或者：

update foo 
  set ac_n_circ = nn.new_number
from (
   select id, 
          ac_n_circ,
          row_number() over (order by ac_n_circ) as new_number
   from foo
) nn
where nn.id = foo.id;

这两个语句均假定存在名为 id 。

Both statements assume that there is a primary key column named id.

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