在sql server中有效地将行转换为列

我正在寻找一种有效的方法来转换行到列在SQL服务器，我听说PIVOT不是很快，我需要处理大量的记录。

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        |
---------------------------------------------------------------------

我如何构建结果?

当前回答

有几种方法可以将数据从多行转换为列。

使用主

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;

看到演示。

列名数目未知的枢轴

如果你有一个未知数量的列名，你想要转置，那么你可以使用动态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;

看到演示。

使用聚合函数

如果你不想使用PIVOT函数，那么你可以使用一个带有CASE表达式的聚合函数:

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

看到演示。

使用多个连接

这也可以使用多个连接来完成，但是您将需要一些列来关联示例数据中没有的每一行。但是基本的语法是:

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'

2013-04-01 14:13:33

其他回答

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

2021-04-07 15:30:22

这更像是一个方法，而不仅仅是一个脚本，它为您提供了更大的灵活性。

首先有3个对象:

用户定义的表类型[ColumnActionList] ->保存数据为参数 SP [proc_PivotPrepare] ->准备数据 SP [proc_PivotExecute] ->执行脚本

创建类型[dbo]。[ColumnActionList] AS TABLE （ [ID] [smallint] NOT NULL， [ColumnName] nvarchar NOT NULL， [操作]nchar NOT 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DB和表名)，你将为第二个SP得到一个预先创建的执行查询，你所要做的就是从你的源定义列: +稳定 + Value(将用于在此基础上集中值) + Dim(你想用来做主元的列)

名称和数据类型将自动定义!

我不推荐它用于任何生产环境，但它可以用于特殊的BI请求。

2017-01-23 16:01:02

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

2022-02-20 05:46:53

我修改了Taryn的答案(“columnnames数量未知的枢轴”版本)，以在结果中显示超过1行。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;

2022-12-02 21:43:41

有几种方法可以将数据从多行转换为列。

使用主

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;

看到演示。

列名数目未知的枢轴

如果你有一个未知数量的列名，你想要转置，那么你可以使用动态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;

看到演示。

使用聚合函数

如果你不想使用PIVOT函数，那么你可以使用一个带有CASE表达式的聚合函数:

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

看到演示。

使用多个连接

这也可以使用多个连接来完成，但是您将需要一些列来关联示例数据中没有的每一行。但是基本的语法是:

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'

2013-04-01 14:13:33

在sql server中有效地将行转换为列

推荐文章

最新文章

标签