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HomeDatabaseMysql TutorialSQL Server中行转列问题的终极解决

本文将向大家介绍 SQL Server 中行 转列 问题 的 终极 解决 方案,主要应用case语句来 解决 行转列的 问题 ,下面就一起来看看。 行转列 问题 主要分为两类。 1)简单的行转列 问题 : 示例表: idsidcourse result 1 2005001 语文80.0 2 2005001 数学90.0 3 20

  本文将向大家介绍 SQL Server 中行转列问题终极解决方案,主要应用case语句来解决行转列的问题,下面就一起来看看。

  行转列问题主要分为两类。

  1)简单的行转列问题:

  示例表:

  id   sid   course   result

  1  2005001 语文    80.0

  2  2005001 数学    90.0

  3  2005001 英语    80.0

  4  2005002 语文    56.0

  5  2005002 数学    69.0

  6  2005002 英语    89.0

  执行:

以下是引用片段:
  select sid,语文=isnull(sum(case course when '语文' then result end),0),
  数学=isnull(sum(case course when '数学' then result end),0),
  英语=isnull(sum(case course when '英语' then result end),0)
  from result
  group by sid
  order by sid

  得出结果:

  sid       语文   数学   英语

  2005001  80.0  90.0  80.0

  2005002  56.0  69.0  89.0

  2)较为复杂的行转列

  表1:course

  id name

  1 语文

  2 数学

  3 英语

  表2:result

  id   sid   course   result

  1  2005001  语文    80.0

  2  2005001  数学    90.0

  3  2005001  英语    80.0

  4  2005002  语文    56.0

  5  2005002  数学    69.0

  6  2005002  英语    89.0

以下是引用片段:
  declare @sql varchar(8000)
  set @sql='select sid'
  select @sql=@sql+','+course.name+'=isnull(sum(case course when '''+course.name+''' then result end),0)'
  from course order by id
  set @sql=@sql+' from result group by sid order by sid'
  print @sql
  exec(@sql)

  得出结果

  sid       语文    数学   英语

  2005001  80.0  90.0  80.0

  2005002  56.0  69.0  89.0

  点击查看原文>>

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