在 sql server 中高效地将行转换为列-解网

问：

我正在寻找一种有效的方法在 SQL Server 中将行转换为列，我听说 PIVOT 不是很快，我需要处理大量记录。

这是我的例子：

同上	价值	列名称
1	John	名字
2	2.4	量
3	ZH1E4A	邮政编码
4	叉	姓氏
5	857685	帐号

这是我的结果：

名字	量	邮政编码	姓氏	帐号
John	2.4	ZH1E4A	叉	857685

如何构建结果？

sql sql-server sql-server-2008 透视

答：

734赞 Taryn 4/1/2013 #1

有几种方法可以将多行中的数据转换为列。

用`PIVOT`

在 SQL Server 中，可以使用该函数将数据从行转换为列：PIVOT

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;

请参阅演示。

枢轴数未知`columnnames`

如果要转置的未知数量，则可以使用动态 SQL：columnnames

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;

请参阅演示。

使用聚合函数

如果不想使用该函数，则可以使用带有表达式的聚合函数：PIVOTCASE

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

请参阅演示。

使用多个联接

这也可以使用多个联接来完成，但您需要一些列来关联示例数据中没有的每一行。但基本语法是：

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'

7赞 Gordon Linoff 4/1/2013

+1 . . .但在最后一个示例中，您可以使用而不是，因为每个子查询返回一行。cross joinleft join

1赞 tbag 4/1/2013

我需要构建一个动态查询，因为我不知道行数。让我们谈谈转换一个包含 10.000.000 数百万条记录的表

12赞 Taryn 4/1/2013

@tbag 如果您的行数未知，那么您将不得不使用动态 sql，但请注意，转换数百万行不会有效。

1赞 tbag 4/1/2013

我不能使用视图进行转换，使用 TFV 怎么样？这就是为什么我一直在寻找一个有效的解决方案。

4赞 Taryn 4/1/2013

@tbag动态 SQL 不能在视图或表值函数中使用，则必须在存储过程中使用

13赞 Bartosz X 1/24/2017 #2

这不仅仅是一个脚本，而是一种方法，而是为您提供了更大的灵活性。

首先，有 3 个对象：

用户定义的 TABLE 类型 [] -> 保存数据为参数ColumnActionList
SP [] -> 准备我们的数据proc_PivotPrepare
SP [] ->执行脚本proc_PivotExecute

创建类型 [dbo]。[列操作列表]作为表 ( [ID] [smallint] 不为 NULL， [列名] nvarchar 不为空， [操作] nchar 不为 NULL ); 去

    CREATE PROCEDURE [dbo].[proc_PivotPrepare] 
    (
    @DB_Name        nvarchar(128),
    @TableName      nvarchar(128)
    )
    AS
            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;

GO

CREATE PROCEDURE [dbo].[sp_PivotExecute]
(
@ColumnListWithActions  ColumnActionList ReadOnly
,@TableName                     nvarchar(128)
)
AS


--#######################################################################################################################
--###| 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 [xxx_ID_xxx] = 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 xxx_ID_xxx = 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.[xxx_ID_xxx] '
                                    + ' 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([xxx_ID_xxx]) 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([xxx_ID_xxx]) FROM ##FinalTab)
                                        BEGIN
                                            SELECT @x = 1
                                            SELECT @FinalCode = @FinalCode 
                                                                                + ' LEFT JOIN (SELECT ' +  @ListOfColumns_Stable + ' , ' + @ListOfColumns_Variable 
                                                                                + ' FROM ##FinalTab WHERE [xxx_ID_xxx] = ' 
                                                                                + 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）开始，您将获得第二个 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（将用于在此基础上集中值） + Dim（要用于透视的列）

名称和数据类型将自动定义！

我不能将其推荐用于任何生产环境，但可以用于临时 BI 请求。

0赞 FAB 9/20/2018

一切都很好，直到有什么建议吗？Could not find stored procedure 'dbo.sp_PivotIt'.

0赞 Bartosz X 9/24/2018

@DarXyde sory 我必须混合 2 个版本，请重新编译并重试

0赞 FAB 9/26/2018

谢谢 Bartosz，设法使用了您脚本中的一些想法，并完成了我已经想到的事情，但尽管如此，还是感谢您:)更新它。我本来应该考虑更改那行，但老实说，您忘记了存储过程不是系统中的默认值或类似的东西。当我再次接近该项目时，我会试一试，并在这里更新！

1赞 FAB 9/26/2018

仍然是SP的错误名称，但现在我知道出了什么问题，很容易修复：更改为.sp_Pivot_Executeproc_PivotExecute

0赞 Bartosz X 9/26/2018

@DarXyde - 谢谢，发现这一点 - 现在已经修复

0赞 Md. Nazmul Alom 4/7/2021 #3

请尝试

CREATE TABLE pvt (Present int, [Absent] int);
GO
INSERT INTO pvt VALUES (10,40);
GO
--Unpivot the table.
SELECT Code, Value
FROM 
   (SELECT Present, Absent
   FROM pvt) p
UNPIVOT
   (Value FOR Code IN 
      (Present, [Absent])
)AS unpvt;
GO

DROP TABLE pvt

4赞 Eyeslandic 4/8/2021

这如何改进已经接受的答案？

2赞 Ronen Ariely 2/20/2022 #4

另一个非常有用的选项是使用 CROSS APPLY

-- Original data
SELECT * FROM (VALUES ('1', 1, 2, 3),('2', 11, 22, 33)) AS Stage(id,col1,col2,col3)

-- row to columns using CROSS APPLY
SELECT Stage.id,v.idd, v.colc
FROM (VALUES ('1', 1, 2, 3),('2', 11, 22, 33)) AS Stage(id,col1,col2,col3)
CROSS APPLY (VALUES ('col1', col1),('col2', col2),('col3', col3)) AS v(idd,colc)
GO

0赞 Seth 11/1/2023

我喜欢这种方式，但这似乎是的替代品，而不是的替代品。也就是说，代码示例中的注释实际上应该被记录为CROSS APPLYUNPIVOTPIVOT-- row to columns using CROSS APPLY-- columns to rows using CROSS APPLY

7赞 The One 12/3/2022 #5

我修改了 Taryn 的答案（“列名数量未知的透视”版本）以在结果中显示 1 行以上。这需要有一个额外的“组”列

DROP TABLE #yourtable
CREATE table #yourtable
    ([Id] int,[Group] int, [Value] varchar(6), [ColumnName] varchar(13))
;
    
INSERT INTO #yourtable
    ([Id],[Group], [Value], [ColumnName])
VALUES
    (1,1, 'John', 'FirstName'),
    (2,1, '2.4', 'Amount'),
    (3,1, 'ZH1E4A', 'PostalCode'),
    (4,1, 'Fork', 'LastName'),
    (5,1, '857685', 'AccountNumber'),
    (6,2, 'Pedro', 'FirstName'),
    (7,2, '5.1', 'Amount'),
    (8,2, '123456', 'PostalCode'),
    (9,2, 'Torres', 'LastName'),
    (10,2, '857686', 'AccountNumber')
;
;



DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT ',' + QUOTENAME(ColumnName) 
                    from #yourtable
                    group by [Group], ColumnName, id
                    having [group] = (SELECT TOP 1 MIN([Group])FROM #yourtable)
                    order by id
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')


        

set @query = N'SELECT ' + @cols + N' from 
             (
                select value, ColumnName,[Group]
                from #yourtable
                GROUP BY [Group],ColumnName,Value
            ) x
            pivot 
            (
                max(value)
                for ColumnName in (' + @cols + N')
            ) p '



exec sp_executesql @query;

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在 sql server 中高效地将行转换为列

Efficiently convert rows to columns in sql server

评论

用`PIVOT`

枢轴数未知`columnnames`

使用聚合函数

使用多个联接

评论

评论

评论

评论

在 sql server 中高效地将行转换为列

Efficiently convert rows to columns in sql server

评论

用PIVOT

枢轴数未知columnnames

使用聚合函数

使用多个联接

评论

评论

评论

评论

用`PIVOT`

枢轴数未知`columnnames`