数据记录行转列

数据库有Score表的数据如下：

tname	subject	score
stu1	Chinese	80
stu1	English	60
stu1	Math	75
stu2	Chinese	80
stu2	English	85
stu3	Chinese	85
stu3	Math	90

 

需要行列转换，获取下列视图：

tname	Chinese	English	Math
stu1	80	60	75
stu2	80	85
stu3	85		90

 

如何通过SQL代码实现呢？ 下面针对SQL 2000/2005 分别给出了方法：

 

--SQL2000 静态 sql

SELECT tname,

                Chinese = MAX(CASE subject WHEN 'Chinese' THEN score ELSE 0 END),

                English = MAX(CASE subject WHEN 'English' THEN score ELSE 0 END),

                Math = MAX(CASE subject WHEN 'Math' THEN score ELSE 0 END)

FROM teammember

GROUP BY tname

ORDER BY tname

 

--SQL2000 动态 sql

DECLARE @sql NVARCHAR(4000)

SET @sql = 'SELECT tname'

SELECT  @sql = @sql + ', ' + a.subject + ' = MAX(CASE subject WHEN ''' + a.subject + ''' THEN score ELSE 0 END)'

                FROM (SELECT DISTINCT subject FROM teammember) a ORDER BY subject

SET @sql = @sql + ' FROM teammember GROUP BY tname ORDER BY tname'

EXEC(@sql)

 

--SQL2005 静态 sql

SELECT * FROM (SELECT * FROM teammember) a PIVOT (MAX(score) FOR subject IN (Chinese, English, Math)) b

 

--SQL2005 动态 sql

DECLARE @sql NVARCHAR(4000)

SELECT @sql = ISNULL(@sql + ',' , '') + subject FROM teammember GROUP BY subject

EXEC ('SELECT * FROM (SELECT * FROM teammember) a PIVOT (MAX(score) FOR subject IN (' + @sql + ')) b')