在SQL Server中有效地将行转换为列
我正在寻找一种有效的方式将行转换为SQL服务器中的列，我听说PIVOT不是很快，我需要处理大量的logging。
这是我的例子：
---------------------------- | Id | Value |ColumnName | ---------------------------- | 1 |John |FirstName | | 2 |2.4 | Amount | | 3 |ZH1E4A |PostalCode | | 4 |Fork |LastName | | 5 |857685 |AccountNumber| ---------------------------- 这是我的结果：
-------------------------------------------------------------------- |FirstName |Amount| PostalCode | LastName | AccountNumber| -------------------------------------------------------------------- |John | 2.4 | ZH1E4A | Fork | 857685 | --------------------------------------------------------------------
我如何build立结果？
有几种方法可以将数据从多行转换为列。 在SQL Server中，您可以使用PIVOT函数将数据从行转换为列：
select Firstname, Amount, PostalCode, LastName, AccountNumber from ( select value, columnname from yourtable ) d pivot ( max(value) for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber) ) piv;
看演示 。
如果您要转置的columnnames数量未知，则可以使用dynamicSQL：
DECLARE @cols AS NVARCHAR(MAX), @query AS NVARCHAR(MAX) select @cols = STUFF((SELECT ',' + QUOTENAME(ColumnName) from yourtable group by ColumnName, id order by id FOR XML PATH(''), TYPE ).value('.', 'NVARCHAR(MAX)') ,1,1,'') set @query = N'SELECT ' + @cols + N' from ( select value, ColumnName from yourtable ) x pivot ( max(value) for ColumnName in (' + @cols + N') ) p ' exec sp_executesql @query;
看演示 。
如果你不想使用PIVOT函数，那么你可以使用CASEexpression式的聚合函数：
select max(case when columnname = 'FirstName' then value end) Firstname, max(case when columnname = 'Amount' then value end) Amount, max(case when columnname = 'PostalCode' then value end) PostalCode, max(case when columnname = 'LastName' then value end) LastName, max(case when columnname = 'AccountNumber' then value end) AccountNumber from yourtable
看演示 。
这也可以使用多个连接完成，但是您需要一些列来关联样例数据中没有的每一行。 但基本的语法是：
select fn.value as FirstName, a.value as Amount, pc.value as PostalCode, ln.value as LastName, an.value as AccountNumber from yourtable fn left join yourtable a on fn.somecol = a.somecol and a.columnname = 'Amount' left join yourtable pc on fn.somecol = pc.somecol and pc.columnname = 'PostalCode' left join yourtable ln on fn.somecol = ln.somecol and ln.columnname = 'LastName' left join yourtable an on fn.somecol = an.somecol and an.columnname = 'AccountNumber' where fn.columnname = 'Firstname'
由于数据的旋转仍然是一个热门的数据，我决定添加一些forms。 这不仅仅是一个单一的脚本，而是一个方法，但给你更多的可能性。 首先有3个脚本需要部署：1）用户定义TABLEtypes[ ColumnActionList ] – >保存数据为参数2）SP [ proc_PivotPrepare ] – >准备我们的数据3）SP [ proc_PivotExecute ] – >执行脚本
CREATE TYPE [dbo].[ColumnActionList] AS TABLE( [ID] [smallint] NOT NULL, [ColumnName] [nvarchar](128) NOT NULL, [Action] [nchar](1) NOT NULL ); GO CREATE PROCEDURE [dbo].[proc_PivotPrepare] ( @DB_Name nvarchar(128), @TableName nvarchar(128) ) AS ---------------------------------------------------------------------------------------------------- -----| Author: Bartosz ---------------------------------------------------------------------------------------------------- SELECT @DB_Name = ISNULL(@DB_Name,db_name()) DECLARE @SQL_Code nvarchar(max) DECLARE @MyTab TABLE (ID smallint identity(1,1), [Column_Name] nvarchar(128), [Type] nchar(1), [Set Action SQL] nvarchar(max)); SELECT @SQL_Code = 'SELECT [<| SQL_Code |>] = '' '' ' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''-----| Declare user defined type [ID] / [ColumnName] / [PivotAction] '' ' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''DECLARE @ColumnListWithActions ColumnActionList;''' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''-----| Set [PivotAction] (''''S'''' as default) to select dimentions and values '' ' + 'UNION ALL ' + 'SELECT ''-----|''' + 'UNION ALL ' + 'SELECT ''-----| ''''S'''' = Stable column || ''''D'''' = Dimention column || ''''V'''' = Value column '' ' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''INSERT INTO @ColumnListWithActions VALUES ('' + CAST( ROW_NUMBER() OVER (ORDER BY [NAME]) as nvarchar(10)) + '', '' + '''''''' + [NAME] + ''''''''+ '', ''''S'''');''' + 'FROM [' + @DB_Name + '].sys.columns ' + 'WHERE object_id = object_id(''[' + @DB_Name + ']..[' + @TableName + ']'') ' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''-----| Execute sp_PivotIT with parameters: columns and dimentions and main table name'' ' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''EXEC [dbo].[sp_PivotIt] @ColumnListWithActions, ' + '''''' + @TableName + '''''' + ';''' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' EXECUTE SP_EXECUTESQL @SQL_Code; GO CREATE PROCEDURE [dbo].[proc_PivotExecute] ( @ColumnListWithActions ColumnActionList ReadOnly ,@TableName nvarchar(128) ) AS --####################################################################################################################### --###| Author: Bartosz --####################################################################################################################### --####################################################################################################################### --###| Step 1 - Select our user-defined-table-variable into temp table --####################################################################################################################### IF OBJECT_ID('tempdb.dbo.#ColumnListWithActions', 'U') IS NOT NULL DROP TABLE #ColumnListWithActions; SELECT * INTO #ColumnListWithActions FROM @ColumnListWithActions; --####################################################################################################################### --###| Step 2 - Preparing lists of column groups as strings: --####################################################################################################################### DECLARE @ColumnName nvarchar(128) DECLARE @Destiny nchar(1) DECLARE @ListOfColumns_Stable nvarchar(max) DECLARE @ListOfColumns_Dimension nvarchar(max) DECLARE @ListOfColumns_Variable nvarchar(max) --############################ --###| Cursor for List of Stable Columns --############################ DECLARE ColumnListStringCreator_S CURSOR FOR SELECT [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'S' OPEN ColumnListStringCreator_S; FETCH NEXT FROM ColumnListStringCreator_S INTO @ColumnName WHILE @@FETCH_STATUS = 0 BEGIN SELECT @ListOfColumns_Stable = ISNULL(@ListOfColumns_Stable, '') + ' [' + @ColumnName + '] ,'; FETCH NEXT FROM ColumnListStringCreator_S INTO @ColumnName END CLOSE ColumnListStringCreator_S; DEALLOCATE ColumnListStringCreator_S; --############################ --###| Cursor for List of Dimension Columns --############################ DECLARE ColumnListStringCreator_D CURSOR FOR SELECT [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'D' OPEN ColumnListStringCreator_D; FETCH NEXT FROM ColumnListStringCreator_D INTO @ColumnName WHILE @@FETCH_STATUS = 0 BEGIN SELECT @ListOfColumns_Dimension = ISNULL(@ListOfColumns_Dimension, '') + ' [' + @ColumnName + '] ,'; FETCH NEXT FROM ColumnListStringCreator_D INTO @ColumnName END CLOSE ColumnListStringCreator_D; DEALLOCATE ColumnListStringCreator_D; --############################ --###| Cursor for List of Variable Columns --############################ DECLARE ColumnListStringCreator_V CURSOR FOR SELECT [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'V' OPEN ColumnListStringCreator_V; FETCH NEXT FROM ColumnListStringCreator_V INTO @ColumnName WHILE @@FETCH_STATUS = 0 BEGIN SELECT @ListOfColumns_Variable = ISNULL(@ListOfColumns_Variable, '') + ' [' + @ColumnName + '] ,'; FETCH NEXT FROM ColumnListStringCreator_V INTO @ColumnName END CLOSE ColumnListStringCreator_V; DEALLOCATE ColumnListStringCreator_V; SELECT @ListOfColumns_Variable = LEFT(@ListOfColumns_Variable, LEN(@ListOfColumns_Variable) - 1); SELECT @ListOfColumns_Dimension = LEFT(@ListOfColumns_Dimension, LEN(@ListOfColumns_Dimension) - 1); SELECT @ListOfColumns_Stable = LEFT(@ListOfColumns_Stable, LEN(@ListOfColumns_Stable) - 1); --####################################################################################################################### --###| Step 3 - Preparing table with all possible connections between Dimension columns excluding NULLs --####################################################################################################################### DECLARE @DIM_TAB TABLE ([DIM_ID] smallint, [ColumnName] nvarchar(128)) INSERT INTO @DIM_TAB SELECT [DIM_ID] = ROW_NUMBER() OVER(ORDER BY [ColumnName]), [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'D'; DECLARE @DIM_ID smallint; SELECT @DIM_ID = 1; DECLARE @SQL_Dimentions nvarchar(max); IF OBJECT_ID('tempdb.dbo.##ALL_Dimentions', 'U') IS NOT NULL DROP TABLE ##ALL_Dimentions; SELECT @SQL_Dimentions = 'SELECT ID = ROW_NUMBER() OVER (ORDER BY ' + @ListOfColumns_Dimension + '), ' + @ListOfColumns_Dimension + ' INTO ##ALL_Dimentions ' + ' FROM (SELECT DISTINCT' + @ListOfColumns_Dimension + ' FROM ' + @TableName + ' WHERE ' + (SELECT [ColumnName] FROM @DIM_TAB WHERE [DIM_ID] = @DIM_ID) + ' IS NOT NULL '; SELECT @DIM_ID = @DIM_ID + 1; WHILE @DIM_ID <= (SELECT MAX([DIM_ID]) FROM @DIM_TAB) BEGIN SELECT @SQL_Dimentions = @SQL_Dimentions + 'AND ' + (SELECT [ColumnName] FROM @DIM_TAB WHERE [DIM_ID] = @DIM_ID) + ' IS NOT NULL '; SELECT @DIM_ID = @DIM_ID + 1; END SELECT @SQL_Dimentions = @SQL_Dimentions + ' )x'; EXECUTE SP_EXECUTESQL @SQL_Dimentions; --####################################################################################################################### --###| Step 4 - Preparing table with all possible connections between Stable columns excluding NULLs --####################################################################################################################### DECLARE @StabPos_TAB TABLE ([StabPos_ID] smallint, [ColumnName] nvarchar(128)) INSERT INTO @StabPos_TAB SELECT [StabPos_ID] = ROW_NUMBER() OVER(ORDER BY [ColumnName]), [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'S'; DECLARE @StabPos_ID smallint; SELECT @StabPos_ID = 1; DECLARE @SQL_MainStableColumnTable nvarchar(max); IF OBJECT_ID('tempdb.dbo.##ALL_StableColumns', 'U') IS NOT NULL DROP TABLE ##ALL_StableColumns; SELECT @SQL_MainStableColumnTable = 'SELECT ID = ROW_NUMBER() OVER (ORDER BY ' + @ListOfColumns_Stable + '), ' + @ListOfColumns_Stable + ' INTO ##ALL_StableColumns ' + ' FROM (SELECT DISTINCT' + @ListOfColumns_Stable + ' FROM ' + @TableName + ' WHERE ' + (SELECT [ColumnName] FROM @StabPos_TAB WHERE [StabPos_ID] = @StabPos_ID) + ' IS NOT NULL '; SELECT @StabPos_ID = @StabPos_ID + 1; WHILE @StabPos_ID <= (SELECT MAX([StabPos_ID]) FROM @StabPos_TAB) BEGIN SELECT @SQL_MainStableColumnTable = @SQL_MainStableColumnTable + 'AND ' + (SELECT [ColumnName] FROM @StabPos_TAB WHERE [StabPos_ID] = @StabPos_ID) + ' IS NOT NULL '; SELECT @StabPos_ID = @StabPos_ID + 1; END SELECT @SQL_MainStableColumnTable = @SQL_MainStableColumnTable + ' )x'; EXECUTE SP_EXECUTESQL @SQL_MainStableColumnTable; --####################################################################################################################### --###| Step 5 - Preparing table with all options ID --####################################################################################################################### DECLARE @FULL_SQL_1 NVARCHAR(MAX) SELECT @FULL_SQL_1 = '' DECLARE @i smallint IF OBJECT_ID('tempdb.dbo.##FinalTab', 'U') IS NOT NULL DROP TABLE ##FinalTab; SELECT @FULL_SQL_1 = 'SELECT t.*, dim.[ID] ' + ' INTO ##FinalTab ' + 'FROM ' + @TableName + ' t ' + 'JOIN ##ALL_Dimentions dim ' + 'ON t.' + (SELECT [ColumnName] FROM @DIM_TAB WHERE [DIM_ID] = 1) + ' = dim.' + (SELECT [ColumnName] FROM @DIM_TAB WHERE [DIM_ID] = 1); SELECT @i = 2 WHILE @i <= (SELECT MAX([DIM_ID]) FROM @DIM_TAB) BEGIN SELECT @FULL_SQL_1 = @FULL_SQL_1 + ' AND t.' + (SELECT [ColumnName] FROM @DIM_TAB WHERE [DIM_ID] = @i) + ' = dim.' + (SELECT [ColumnName] FROM @DIM_TAB WHERE [DIM_ID] = @i) SELECT @i = @i +1 END EXECUTE SP_EXECUTESQL @FULL_SQL_1 --####################################################################################################################### --###| Step 6 - Selecting final data --####################################################################################################################### DECLARE @STAB_TAB TABLE ([STAB_ID] smallint, [ColumnName] nvarchar(128)) INSERT INTO @STAB_TAB SELECT [STAB_ID] = ROW_NUMBER() OVER(ORDER BY [ColumnName]), [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'S'; DECLARE @VAR_TAB TABLE ([VAR_ID] smallint, [ColumnName] nvarchar(128)) INSERT INTO @VAR_TAB SELECT [VAR_ID] = ROW_NUMBER() OVER(ORDER BY [ColumnName]), [ColumnName] FROM #ColumnListWithActions WHERE [Action] = 'V'; DECLARE @y smallint; DECLARE @x smallint; DECLARE @z smallint; DECLARE @FinalCode nvarchar(max) SELECT @FinalCode = ' SELECT ID1.*' SELECT @y = 1 WHILE @y <= (SELECT MAX([ID]) FROM ##FinalTab) BEGIN SELECT @z = 1 WHILE @z <= (SELECT MAX([VAR_ID]) FROM @VAR_TAB) BEGIN SELECT @FinalCode = @FinalCode + ', [ID' + CAST((@y) as varchar(10)) + '.' + (SELECT [ColumnName] FROM @VAR_TAB WHERE [VAR_ID] = @z) + '] = ID' + CAST((@y + 1) as varchar(10)) + '.' + (SELECT [ColumnName] FROM @VAR_TAB WHERE [VAR_ID] = @z) SELECT @z = @z + 1 END SELECT @y = @y + 1 END SELECT @FinalCode = @FinalCode + ' FROM ( SELECT * FROM ##ALL_StableColumns)ID1'; SELECT @y = 1 WHILE @y <= (SELECT MAX([ID]) FROM ##FinalTab) BEGIN SELECT @x = 1 SELECT @FinalCode = @FinalCode + ' LEFT JOIN (SELECT ' + @ListOfColumns_Stable + ' , ' + @ListOfColumns_Variable + ' FROM ##FinalTab WHERE [ID] = ' + CAST(@y as varchar(10)) + ' )ID' + CAST((@y + 1) as varchar(10)) + ' ON 1 = 1' WHILE @x <= (SELECT MAX([STAB_ID]) FROM @STAB_TAB) BEGIN SELECT @FinalCode = @FinalCode + ' AND ID1.' + (SELECT [ColumnName] FROM @STAB_TAB WHERE [STAB_ID] = @x) + ' = ID' + CAST((@y+1) as varchar(10)) + '.' + (SELECT [ColumnName] FROM @STAB_TAB WHERE [STAB_ID] = @x) SELECT @x = @x +1 END SELECT @y = @y + 1 END SELECT * FROM ##ALL_Dimentions; EXECUTE SP_EXECUTESQL @FinalCode; --#######################################################################################################################
从执行第一个查询（通过传递源数据库和表名），你将得到一个预先创build的第二个SP的执行查询，你所要做的就是定义是源的列：+ Stable + Value（将被使用集中基于这个值）+昏暗（你想用来透视的列）
名称和数据types将自动定义！
我不能推荐它用于任何生产环境，但为专门的BI请求做的工作。
另请参阅有关以下内容的好文章： 在SQL Server中将行转换为列（PIVOT）和列转换为行（UNPIVOT）
