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','010000','01','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','010000','01','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','010000','01','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','010000','02','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','010000','02','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','020000','02','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','020000','02','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','020000','02','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','020000','03','采购费',2016,100000.00,80000.00,60000.00,GETDATE());
4. 参考资料
http://www.cnblogs.com/zhangzt/archive/2010/07/29/1787825.html
http://www.cnblogs.com/gaizai/p/3753296.html