举例说明怎么用SQL做数据透视表:
[表一 学生信息表]
[表二 课程信息表]
[表三 成绩信息表]
生成基础数据的代码
CREATE TABLE [dbo].[StuInfo] (
[StuID] [char] (6) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[StuName] [varchar] (20) COLLATE Chinese_PRC_CI_AS NOT NULL
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[CourseInfo] (
[CourseID] [char] (6) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[CourseName] [varchar] (20) COLLATE Chinese_PRC_CI_AS NOT NULL
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[ScoreInfo] (
[StuID] [char] (6) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[CourseID] [char] (6) COLLATE Chinese_PRC_CI_AS NOT NULL ,
[Score] [float] NULL
) ON [PRIMARY]
GO
insert stuInfo(StuID,StuName) values ('090301','张三')
insert stuInfo(StuID,StuName) values ('090302','李四')
insert stuInfo(StuID,StuName) values ('090303','王五')
insert CourseInfo(CourseID,CourseName) values ('201001','数学')
insert CourseInfo(CourseID,CourseName) values ('201002','C语言')
insert ScoreInfo(StuID,CourseID,Score) values ('090301','201001',90)
insert ScoreInfo(StuID,CourseID,Score) values ('090301','201002',100)
insert ScoreInfo(StuID,CourseID,Score) values ('090302','201001',95)
insert ScoreInfo(StuID,CourseID,Score) values ('090302','201002',98)
insert ScoreInfo(StuID,CourseID,Score) values ('090303','201001',88)
生成数据透视表
(1)单表 ScoreInfo
declare @sql nvarchar(500)
set @sql = 'SELECT [StuID], '
select @sql = @sql + 'sum(case CourseID when '+quotename(CourseID,'''')+' then score else 0 end) as ' + quotename(CourseID)+',' from ScoreInfo group by CourseID
select @sql = left(@sql,len(@sql)-1)
select @sql = @sql + ', sum(score) as [sum] from ScoreInfo group by [StuID]'
select @sql
exec(@sql)
执行效果图:
(2)双表 StuInfo,ScoreInfo
declare @sql nvarchar(500)
set @sql = 'SELECT (select stuName from StuInfo where StuInfo.stuID=scoreInfo.stuID), '
select @sql = @sql + 'sum(case CourseID when '+quotename(CourseID,'''')+' then score else 0 end) as ' + quotename(CourseID)+',' from ScoreInfo group by CourseID
select @sql = left(@sql,len(@sql)-1)
select @sql = @sql + ', sum(score) as [sum] from ScoreInfo group by [StuID]'
select @sql
exec(@sql)
执行效果图:
(3)多表 StuInfo,ScoreInfo,ScoreInfo
declare @sql nvarchar(500)
set @sql = 'SELECT (select stuName from StuInfo where StuInfo.stuID=scoreInfo.stuID) as stuName, '
select @sql = @sql + 'sum(case CourseID when '+quotename(CourseID,'''')+' then score else 0 end) as ' + quotename((select courseName from courseInfo where
courseInfo.CourseID=ScoreInfo.CourseID),'''')+',' from ScoreInfo group by CourseID
select @sql = left(@sql,len(@sql)-1)
select @sql = @sql + ', sum(score) as [sum] from ScoreInfo group by [StuID]'
select @sql
exec(@sql)
执行效果图:
用SQL做数据透视表主要分两步:
用SQL语句按条件汇总各表、各文件数据
用EXCEL的数据透视表透视
其实说白了SQL在这个过程中就是形成数据源的过程,做透视表还是用的EXCEL来做的,只是在用SQL生成完数据自动的会有个选项问你要不要做透视,选”是“的话就直接跳出透视表的窗口,选”否“的话可以把数据源返回到EXCEL表中。
excel从其他表中提取数据,生成的数据的时候,会有选项,你生成表还是透视表,这个过程中,可以使用sql语言进行处理,比如多表汇总、合并、筛选、计算。