SQL SERVER 中的行列转换小结

1. 介绍说明

前段时间组内的小伙伴在升级维护项目中，经常涉及一些复杂的数据转换问题，让我去看下有些地方怎么处理，我发现好多都是涉及到行列转换的问题，处理起来经常会比较麻烦，借此也总结一下，方便以后的查阅使用。该总结参照了网上的一些资料，也做了一些变动，如有更好的方法也欢迎指出。

演示的脚本见 3.测试数据脚本

2. 例子演示

2.1 实现行转列

(1) Case WHEN 实现行转列

/*-----1.1 Case WHEN 实现行转列----------*/

--(1)静态SQL

SELECT [姓名],

 max(CASE 课程 WHEN '语文' THEN 分数 ELSE 0 end) AS 语文,

 max(CASE 课程 WHEN '数学' THEN 分数 ELSE 0 end)AS 数学,

 max(CASE 课程 WHEN '物理' THEN 分数 ELSE 0 end)AS 物理,

 SUM(分数) AS 总分,

 AVG(分数) AS 平均分

FROM tbScore GROUP BY [姓名]

--(2)动态SQL

DECLARE @sql VARCHAR(500)

SET @sql = 'SELECT [姓名]'

SELECT  @sql = @sql + ',MAX(CASE [课程] WHEN ''' + [课程] + ''' THEN [分数] ELSE 0 END)[' + [课程] + ']'

FROM    (

            SELECT DISTINCT [课程] FROM tbScore

        ) T1

--同FROM tbScore  GROUP BY [课程]，默认按课程名排序

SET @sql = @sql + ' FROM tbScore GROUP BY [姓名]'

PRINT '@sql: ' + @sql

EXEC(@sql)

(2) PIVOT 实现行转列，其中的NULL值发现还不好处理为0

--(1)静态SQL

SELECT  [姓名] ,

        [语文] ,

        [数学] ,

        [物理]

FROM    ( SELECT    [分数] ,

                    [课程] ,

                    [姓名]

          FROM      tbScore

        ) AS SourceTable PIVOT ( AVG([分数]) FOR [课程] IN ( 语文, 数学, 物理 ) ) T

--(2)动态SQL

DECLARE @sql2 VARCHAR(8000)

SET @sql2 = ''

SELECT @sql2 = @sql2 + ',' + [课程] FROM dbo.tbScore GROUP BY [课程]

--STUFF： 删除指定长度的字符，并在指定的起点处插入另一组字符。

SET @sql2= STUFF(@sql2,1,1,'')  --去掉首个','

SET @sql2 = 'SELECT [姓名],' + @sql2 + ' FROM (SELECT [分数],[课程],[姓名] FROM tbScore ) AS SourceTable PIVOT ( AVG([分数]) FOR [课程] IN ( ' + @sql2 + ') ) T'

PRINT @sql2

EXEC(@sql2)

2.1 实现列转行

(1) UNION 实现列转行

--(1)静态SQL

SELECT * FROM (

    SELECT [姓名],'语文' AS 课程,[语文] AS 分数 ,[日期] FROM tbScoreNew

    UNION ALL

    SELECT [姓名],'数学' AS 课程,[数学] AS 分数 ,[日期] FROM tbScoreNew

    UNION ALL

    SELECT [姓名],'物理' AS 课程,[物理] AS 分数 ,[日期] FROM tbScoreNew

) T ORDER BY [姓名]

--(2)动态SQL

DECLARE @sql3 VARCHAR(8000)

SELECT @sql3 = ISNULL(@sql3 + ' UNION ALL ','') + ' SELECT [姓名],' + QUOTENAME(name,'''') + ' AS 课程,' + QUOTENAME(name) + ',[日期] FROM tbScoreNew'

FROM sys.columns

WHERE object_id = OBJECT_ID('tbScoreNew') AND  name NOT IN ('姓名','日期')

SET @sql3 = 'SELECT * FROM ( ' + @sql3  + ' ) T ORDER BY [姓名]'

PRINT @sql3

EXEC (@sql3)

(2) UNPIVOT 实现列转行

--(1)静态SQL

SELECT * FROM (

    SELECT [姓名],[日期],[语文],[数学],[物理] FROM dbo.tbScoreNew

) T UNPIVOT ([分数] FOR [课程] IN ([语文],[数学],[物理])) T2

ORDER BY [姓名]

--(2)动态SQL

DECLARE @sql4 VARCHAR(8000)

SELECT @sql4 = ISNULL(@sql4 + ',','') + QUOTENAME(name)

FROM sys.columns

WHERE object_id = OBJECT_ID('tbScoreNew') AND  name NOT IN ('姓名','日期')

SET @sql4 = 'SELECT * FROM ( SELECT [姓名],[日期],' + @sql4 + ' FROM dbo.tbScoreNew ) T UNPIVOT ([分数] FOR [课程] IN ('+ @sql4 +')) T2 ORDER BY [姓名]'

PRINT @sql4

EXEC (@sql4)

2.3 动态增加列实现行转列

这个参照部门小伙伴的项目上的要求写的一个例子，由于涉及的转换列同时有多个字段，用上面的行列转换处理起来都很不方便，所以采用比较普通的动态增加列的方式处理

测试数据脚本为附件脚本中的 “3.动态增加列实现行转列" 脚本

要求: 将【部门预算】、【实际预算】、【剩余预算】按照年份横向统计显示，且统计数据按部门、项目分组显示

CREATE TABLE #tmpYear

(

    [YEAR] INT,

    ID INT IDENTITY

)

--保存最终结果

CREATE TABLE #tmpResult

(

    ID INT IDENTITY,

    DeptCode VARCHAR(20),--部门编码

    DeptName NVARCHAR(100), --部门名称

    ProCode VARCHAR(20),--项目编码

    ProName NVARCHAR(100),--项目名称

    KeyCode VARCHAR(50)

)

GO

--1.写入分组数据

INSERT INTO #tmpResult( DeptCode ,DeptName , ProCode ,ProName,KeyCode)

SELECT DeptCode,MAX(DeptName), ProCode,MAX(ProName),DeptCode + '_' + ProCode FROM tbDeptBudget GROUP BY DeptCode,ProCode

--2.计算预算结果数据

--写入年份数据

INSERT INTO #tmpYear SELECT DISTINCT Year FROM dbo.tbDeptBudget

DECLARE @SQL VARCHAR(5000)

DECLARE @ColName1 VARCHAR(50)

DECLARE @ColName2 VARCHAR(50)

DECLARE @ColName3 VARCHAR(50)

DECLARE @Year INT

DECLARE @ID INT

DECLARE @RowNum INT

SET @Year = 0

SET @ID = 1

SET @RowNum = (SELECT COUNT(0) FROM #tmpYear)

WHILE @ID <= @RowNum

BEGIN

    SET @Year = (SELECT [YEAR] FROM #tmpYear WHERE ID = @ID)

    SET @ColName1 = 'Bduget_' + CAST(@Year AS VARCHAR(10))

    SET @ColName2 = 'Fact_' + CAST(@Year AS VARCHAR(10))

    SET @ColName3 = 'Remain_' + CAST(@Year AS VARCHAR(10))

    --增加动态列

    SET @SQL = 'ALTER TABLE #tmpResult ADD ' + @ColName1 + ' Decimal(18,2)'

              + 'ALTER TABLE #tmpResult ADD ' + @ColName2 + ' Decimal(18,2)'

              + 'ALTER TABLE #tmpResult ADD ' + @ColName3 + ' Decimal(18,2)'

    EXEC(@SQL)

    --写入动态列数据

    SET @SQL = 'UPDATE T SET ' + @ColName1 + ' = S.BudgetAmount,' + @ColName2 + ' = S.FactAmount,'+ @ColName3 + ' = S.RemainAmount '

        + ' FROM #tmpResult T INNER JOIN ( '

        + ' SELECT (DeptCode + ' + QUOTENAME('_','''') +' + ProCode) AS KeyCode,MAX(BudgetAmount)AS BudgetAmount ,MAX(FactAmount)AS FactAmount,MAX(RemainAmount)AS RemainAmount '

        + ' FROM dbo.tbDeptBudget WHERE Year= ' + CAST (@Year AS VARCHAR(10))

        + ' GROUP BY DeptCode,ProCode '

        + ') S ON T.KeyCode = S.KeyCode '

    PRINT @SQL

    EXEC(@SQL)

    SET @ID = @ID  + 1

END

--3.返回结果

SELECT * FROM #tmpResult

--4.清理临时表

IF OBJECT_ID('tempdb..#tmpYear') IS NOT NULL

BEGIN

    DROP TABLE #tmpYear

END

IF OBJECT_ID('tempdb..#tmpResult') IS NOT NULL

BEGIN

    DROP TABLE #tmpResult

END

3. 测试数据脚本

/*-----1.行转列的测试数据--------------------------*/

IF OBJECT_ID('tbScore') IS NOT NULL

    DROP TABLE tbScore

GO

CREATE TABLE tbScore

    (

      姓名 VARCHAR(10) ,

      课程 VARCHAR(10) ,

      分数 INT,

      日期 DATETIME

    )

GO

INSERT  INTO tbScore VALUES  ( '张三', '语文', 74,GETDATE() )

--INSERT  INTO tbScore VALUES  ( '张三', '数学', 83 ,GETDATE() )

INSERT  INTO tbScore VALUES  ( '张三', '物理', 93 ,GETDATE() )

INSERT  INTO tbScore VALUES  ( '李四', '语文', 74 ,GETDATE() )

INSERT  INTO tbScore VALUES  ( '李四', '数学', 84 ,GETDATE() )

INSERT  INTO tbScore VALUES  ( '李四', '物理', 94 ,GETDATE() )

GO

/*-----2.列转行的测试数据--------------------------*/

IF OBJECT_ID('tbScoreNew') IS NOT NULL

    DROP TABLE tbScoreNew

GO

CREATE TABLE tbScoreNew(

      姓名 VARCHAR(10) ,

      语文 INT,

      数学 INT,

      物理 INT,

      日期 DATETIME

    )

GO

INSERT  INTO tbScoreNew VALUES  ( '李四', 74,84,94,GETDATE() )

INSERT  INTO tbScoreNew VALUES  ( '张三', 74,83,93,GETDATE() )

GO

/*-----3.动态增加列实现行转列(模拟组内项目要求)--------------------------*/

IF OBJECT_ID('tbDeptBudget') IS NOT NULL

    DROP TABLE tbDeptBudget

GO

--部门预算

CREATE TABLE tbDeptBudget

(

    ID INT IDENTITY(1,1) PRIMARY KEY,

    DeptCode VARCHAR(20),--部门编码

    DeptName NVARCHAR(100), --部门名称

    ProCode VARCHAR(20),--项目编码

    ProName NVARCHAR(100),--项目名称

    Year INT, --年度

    BudgetAmount DECIMAL(18,2), --预算金额

    FactAmount DECIMAL(18,2), --实际金额

    RemainAmount DECIMAL(18,2), --剩余金额

    CreateTime DATETIME  --创建时间

)

GO

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('人事部','','','差旅费',2014,100000.00,80000.00,20000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('人事部','','','差旅费',2015,110000.00,90000.00,50000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('人事部','','','差旅费',2016,120000.00,100000.00,80000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('人事部','','','办公用品',2015,200000.00,150000.00,10000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('人事部','','','办公用品',2016,160000.00,120000.00,80000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('财务部','','','办公用品',2014,50000.00,40000.00,0.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('财务部','','','办公用品',2015,50000.00,50000.00,10000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('财务部','','','办公用品',2016,60000.00,50000.00,40000.00,GETDATE());

INSERT INTO tbDeptBudget(DeptName,DeptCode,ProCode,ProName,YEAR,BudgetAmount,FactAmount,RemainAmount,CreateTime)

VALUES('财务部','','','采购费',2016,100000.00,80000.00,60000.00,GETDATE());

测试脚本附件

4. 参考资料

http://www.cnblogs.com/zhangzt/archive/2010/07/29/1787825.html

http://www.cnblogs.com/gaizai/p/3753296.html