filas - pivot y unpivot sql server

Convertir eficientemente las filas en columnas en el servidor SQL

Question

Estoy buscando una forma eficiente de convertir filas en columnas en el servidor SQL, escuché que PIVOT no es muy rápido y que debo lidiar con muchos registros.

Este es mi ejemplo:

   -------------------------------
   | Id | Value  | ColumnName    |
   -------------------------------
   | 1  | John   | FirstName     |
   | 2  | 2.4    | Amount        |
   | 3  | ZH1E4A | PostalCode    |
   | 4  | Fork   | LastName      |
   | 5  | 857685 | AccountNumber |
   -------------------------------

Este es mi resultado:

---------------------------------------------------------------------
| FirstName  |Amount|   PostalCode   |   LastName  |  AccountNumber |
---------------------------------------------------------------------
| John       | 2.4  |   ZH1E4A       |   Fork      |  857685        |
---------------------------------------------------------------------

¿Cómo puedo construir el resultado?

Answer 1

Como los datos pivotantes siguen siendo muy importantes, decidí agregar algo desde mí. Esto es más bien un método que un simple script, pero le ofrece muchas más posibilidades. En primer lugar, hay 3 scripts que necesita implementar: 1) Tipo de TABLE definido por el usuario [ ColumnActionList ] -> contiene datos como parámetro 2) SP [ proc_PivotPrepare ] -> prepara nuestros datos 3) SP [ proc_PivotExecute ] -> ejecuta el script

    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;

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;
--#######################################################################################################################

Desde la ejecución de la primera consulta (al pasar la base de datos de origen y el nombre de la tabla) obtendrá una consulta de ejecución pre-creada para el segundo SP, todo lo que tiene que hacer es definir la columna de su fuente: + Estable + Valor (se usará para concentrar los valores en función de eso) + Degradado (columna que desea utilizar para pivotar)

¡Los nombres y tipos de datos serán definidos automáticamente!

No puedo recomendarlo para ningún entorno de producción, pero hace el trabajo de las solicitudes de BI adhoc.

Answer 2

Hay varias formas de transformar los datos de varias filas en columnas. En SQL Server puede usar la función PIVOT para transformar los datos de filas a columnas:

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;

Ver Demo .

Si tiene un número desconocido de columnnames de columnnames que desea transponer, puede usar SQL dinámico:

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;

Ver Demo .

Si no desea utilizar la función PIVOT , puede usar una función agregada con una expresión CASE :

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

Ver Demo .

Esto también podría completarse utilizando varias combinaciones, pero necesitará alguna columna para asociar cada una de las filas que no tiene en sus datos de muestra. Pero la sintaxis básica sería:

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''