如果SQL Server中的两个连续行是任意的,如何进行比较?
我有一个SQL问题,我不能只用SQL来解决 问题是:我有一个有两列的表。一个是如果SQL Server中的两个连续行是任意的,如何进行比较?,sql,sql-server,tsql,gaps-and-islands,Sql,Sql Server,Tsql,Gaps And Islands,我有一个SQL问题,我不能只用SQL来解决 问题是:我有一个有两列的表。一个是问题(int列),另一个是答案(varchar(1)),如下所示: Question Answer --------+--------- 1 | A 2 | A 3 | C 4 | D 5 | D 6 | D 7 | E 8 | A 9 | B 10 | A 1
问题
(int列),另一个是答案
(varchar(1)
),如下所示:
Question Answer
--------+---------
1 | A
2 | A
3 | C
4 | D
5 | D
6 | D
7 | E
8 | A
9 | B
10 | A
11 | A
12 | A
输出应该是这样的
Range Answer
-----------+----------
1-2 | A
3-3 | C
4-6 | D
7-7 | E
8-8 | A
9-9 | B
10-12 | A
我只是能够做到这一点
select question, answer
from table
order by answer, question asc
很抱歉,我对SQL非常陌生,所以我不知道如何编写此查询。这是一个空白和孤岛问题。您可以使用
row\u number()
枚举答案的值来处理它。这与问题之间的区别是不变的——确定岛屿:
select min(question), max(question), answer
from (select t.*, row_number() over (partition by answer order by question) as seqnum
from t
) t
group by (question - seqnum), answer
order by min(question);
这是一个缺口和孤岛问题。您可以使用
row\u number()
枚举答案的值来处理它。这与问题之间的区别是不变的——确定岛屿:
select min(question), max(question), answer
from (select t.*, row_number() over (partition by answer order by question) as seqnum
from t
) t
group by (question - seqnum), answer
order by min(question);
这是一个缺口和孤岛问题。下面是一种使用行号之间的差异来定义组的方法
select
concat(min(question), '-', max(question)) range,
answer
from (
select
t.*,
row_number() over(order by question) rn1,
row_number() over(partition by answer order by question) rn2
from mytable t
) t
group by answer, rn1 - rn2
order by min(question)
这种方法的优点是,即使
问题
的数字有缺口,它也能工作。这是一个缺口和孤岛问题。下面是一种使用行号之间的差异来定义组的方法
select
concat(min(question), '-', max(question)) range,
answer
from (
select
t.*,
row_number() over(order by question) rn1,
row_number() over(partition by answer order by question) rn2
from mytable t
) t
group by answer, rn1 - rn2
order by min(question)
这种方法的优点是,即使问题
的数字有差距,它也能工作