SQL Server把行转列:
如以下表:
当表中只有少量数据时,可以采用静态SQL语句
如:
select stuName ,
max(case Course when '语文' then score else 0 end) as 语文,
max(case Course when '数学' then score else 0 end) as 数学,
max(case Course when '英语' then score else 0 end) as 英语,
max(case Course when '物理' then score else 0 end) as 物理,
sum(score) as '总分'
from Student group by stuName
max(case Course when '语文' then score else 0 end) as 语文,
max(case Course when '数学' then score else 0 end) as 数学,
max(case Course when '英语' then score else 0 end) as 英语,
max(case Course when '物理' then score else 0 end) as 物理,
sum(score) as '总分'
from Student group by stuName
当数据表中有大量数据,就必须采用动态SQL语句了
如下操作:
declare @name varchar(8000) --声明变量
set @name = 'select stuName '
select @name = @name + ' , sum(case Course when ''' + Course + ''' then score else 0 end) [' + Course + ']'
from (select distinct Course from Student) as a
set @name = @name + ' from Student group by stuName'
exec(@name)
set @name = 'select stuName '
select @name = @name + ' , sum(case Course when ''' + Course + ''' then score else 0 end) [' + Course + ']'
from (select distinct Course from Student) as a
set @name = @name + ' from Student group by stuName'
exec(@name)
其中distinct这个关键字用来过滤掉多余的重复记录只保留一条,但往往只用它来返回不重复记录的条数,而不是用它来返回不重记录的所有值
以上两个结果是一样的,结果如下: