如何为粗体值选择列名？

Question

Cong    BJP      AAP     Winner   Win By
25554   36985    **26929**   BJP      10056
19753   **24569**    36239   AAP      11670

使用Sql server 2008，这是一个投票表，我想从Cong，BJP和AAP列中选择第二个最大投票数，其中列名为结果值 回报 预期结果：

Againstvote  AgainstPartyName
26929           AAP
24569           BJP

Answer 1

select
   case
      when BJP between AAP and Cong then BJP 
      when AAP between BJP and Cong then AAP 
      else Cong
   end as AgainstVote,
   case
      when BJP between AAP and Cong then 'BJP' 
      when AAP between BJP and Cong then 'AAP' 
      else 'Cong'
   end as AgainstPartyName
from tab

Answer 2

您似乎想要一种方法将列名称视为数据的一部分。我会说，这说的是次优设计。无论如何，在你的特殊情况下，有救援的UNPIVOT条款：

SELECT
  Votes     AS AgainstVotes,
  PartyName AS AgainstPartyName
FROM dbo.atable AS t
UNPIVOT (
  Votes FOR PartyName in (BJP, AAP)
) AS u
WHERE PartyName <> Winner
;

UNPIVOT子句将您的数据集转换为：

Cong   PartyName  Votes  Winner  Win By
-----  ---------  -----  ------  ------
25554  BJP        36985  BJP     10056
25554  AAP        26929  BJP     10056
19753  AAP        36239  AAP     11670
19753  BJP        24569  AAP     11670

WHERE子句然后过滤掉获胜选票的行，使参与者丢失。