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I'm looking for an efficient way to convert rows to columns in SQL server, I heard that PIVOT is not very fast, and I need to deal with lot of records. 我正在寻找一种在SQL Server中将行转换为列的有效方法，听说PIVOT速度不是很快，并且我需要处理很多记录。
This is my example: 这是我的示例：
------------------------------- | Id | Value | ColumnName | ------------------------------- | 1 | John | FirstName | | 2 | 2.4 | Amount | | 3 | ZH1E4A | PostalCode | | 4 | Fork | LastName | | 5 | 857685 | AccountNumber | -------------------------------
This is my result: 这是我的结果：
---------------------------------------------------------------------| FirstName |Amount| PostalCode | LastName | AccountNumber |---------------------------------------------------------------------| John | 2.4 | ZH1E4A | Fork | 857685 |---------------------------------------------------------------------
How can I build the result? 如何建立结果？
参考：
There are several ways that you can transform data from multiple rows into columns. 您可以通过多种方式将数据从多行转换为列。
PIVOT 使用PIVOT In SQL Server you can use the PIVOT function to transform the data from rows to columns: 在SQL Server中，可以使用PIVOT函数将数据从行转换为列：
select Firstname, Amount, PostalCode, LastName, AccountNumberfrom( select value, columnname from yourtable) dpivot( max(value) for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber)) piv;
See . 参见 。
columnnames columnnames数量未知的数据透视 If you have an unknown number of columnnames that you want to transpose, then you can use dynamic SQL: 如果要转置的columnnames数量未知，则可以使用动态SQL：
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; See . 参见 。
If you do not want to use the PIVOT function, then you can use an aggregate function with a CASE expression: 如果您不想使用PIVOT函数，则可以将聚合函数与CASE表达式一起使用：
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) AccountNumberfrom yourtable
See . 参见 。
This could also be completed using multiple joins, but you will need some column to associate each of the rows which you do not have in your sample data. 也可以使用多个联接来完成此操作，但是您将需要一些列来关联示例数据中没有的每一行。 But the basic syntax would be: 但基本语法为：
select fn.value as FirstName, a.value as Amount, pc.value as PostalCode, ln.value as LastName, an.value as AccountNumberfrom yourtable fnleft 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'
as pivoting data is still a hot one I decided to add something form me. 由于数据透视仍然很热门，因此我决定添加一些数据。 This is rather a method than just a single script but gives you much more possibilities. 这是一种方法，而不仅仅是一个脚本，但是为您提供了更多的可能性。 First of all There are 3 scripts you need to deploy: 1) User defined TABLE type [ ColumnActionList ] -> holds data as parameter 2) SP [ proc_PivotPrepare ] -> prepares our data 3) SP [ proc_PivotExecute ] -> execute the script 首先，需要部署3个脚本：1）用户定义的TABLE类型[ ColumnActionList ]->将数据作为参数保存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_PivotExecute with parameters: columns and dimentions and main table name'' ' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' + 'UNION ALL ' + 'SELECT ''EXEC [dbo].[sp_PivotExecute] @ColumnListWithActions, ' + '''''' + @TableName + '''''' + ';''' + 'UNION ALL ' + 'SELECT ''----------------------------------------------------------------------------------------------------'' ' EXECUTE SP_EXECUTESQL @SQL_Code;GOCREATE 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 FORSELECT [ColumnName]FROM #ColumnListWithActionsWHERE [Action] = 'S'OPEN ColumnListStringCreator_S;FETCH NEXT FROM ColumnListStringCreator_SINTO @ColumnName WHILE @@FETCH_STATUS = 0 BEGIN SELECT @ListOfColumns_Stable = ISNULL(@ListOfColumns_Stable, '') + ' [' + @ColumnName + '] ,'; FETCH NEXT FROM ColumnListStringCreator_S INTO @ColumnName ENDCLOSE ColumnListStringCreator_S;DEALLOCATE ColumnListStringCreator_S;--############################--###| Cursor for List of Dimension Columns--############################DECLARE ColumnListStringCreator_D CURSOR FORSELECT [ColumnName]FROM #ColumnListWithActionsWHERE [Action] = 'D'OPEN ColumnListStringCreator_D;FETCH NEXT FROM ColumnListStringCreator_DINTO @ColumnName WHILE @@FETCH_STATUS = 0 BEGIN SELECT @ListOfColumns_Dimension = ISNULL(@ListOfColumns_Dimension, '') + ' [' + @ColumnName + '] ,'; FETCH NEXT FROM ColumnListStringCreator_D INTO @ColumnName ENDCLOSE ColumnListStringCreator_D;DEALLOCATE ColumnListStringCreator_D;--############################--###| Cursor for List of Variable Columns--############################DECLARE ColumnListStringCreator_V CURSOR FORSELECT [ColumnName]FROM #ColumnListWithActionsWHERE [Action] = 'V'OPEN ColumnListStringCreator_V;FETCH NEXT FROM ColumnListStringCreator_VINTO @ColumnName WHILE @@FETCH_STATUS = 0 BEGIN SELECT @ListOfColumns_Variable = ISNULL(@ListOfColumns_Variable, '') + ' [' + @ColumnName + '] ,'; FETCH NEXT FROM ColumnListStringCreator_V INTO @ColumnName ENDCLOSE 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; ENDSELECT @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; ENDSELECT @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 smallintIF 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 ENDEXECUTE 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 ENDSELECT * FROM ##ALL_Dimentions;EXECUTE SP_EXECUTESQL @FinalCode;--####################################################################################################################### From executing the first query (by passing source DB and table name) you will get a pre-created execution query for the second SP, all you have to do is define is the column from your source: + Stable + Value (will be used to concentrate values based on that) + Dim (column you want to use to pivot by) 通过执行第一个查询（通过传递源数据库和表名称），您将获得针对第二个SP的预先创建的执行查询，您所要做的就是定义源中的列：+稳定+值（将使用以基于该值集中值）+ Dim（您要用来作为透视依据的列）
Names and datatypes will be defined automatically! 名称和数据类型将自动定义！
I cant recommend it for any production environments but does the job for adhoc BI requests. 我不能将其推荐给任何生产环境，但可以满足即席BI请求的要求。
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