重新编号一组行-数据库问题

Renumbering a set of rows(重新编号一组行)

本文介绍了重新编号一组行的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我有一个包含数据的表格，如下所示:

I have a table with data which looks something like the following:

# the columns #
url
title
group
id_within_group

http://www.google.com
google
search engine
1

http://www.yahoo.com
yahoo
search engine
2

http://www.bing.com
bing
search engine
3

http://www.facebook.com
facebook
social media
1

http://www.twitter.com
twitter
social media
2

如果我这样做

select * from table1 where group = "search engine"

我会得到

http://www.google.com
google
search engine
1

http://www.yahoo.com
yahoo
search engine
2

http://www.bing.com
bing
search engine
3

我希望能够删除这些行中的任何一行，但以某种方式让它重新编号 id_within_group.

I would like to be able to delete any of these rows, but somehow get it to renumber the id_within_group.

所以，如果我从上面的 3 个中删除第二个，它应该自动重新编号然后留给我

SO if I delete the second one from the 3 above, it should automatically renumber then leaving me with

http://www.google.com
google
search engine
1

http://www.bing.com
bing
search engine
2

这可能吗?

推荐答案

如果您只需要显示连续整数，我的建议是在 SELECT 中执行此操作.

My suggestion would be to do this in the SELECT if you just need to display a sequential integer.

SELECT   url             ,
         title           ,
         [group]         ,
         id_within_group ,
         ROW_NUMBER() over (partition BY [group] ORDER BY id_within_group) AS sequential_index
FROM     YourTable

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