Conversion efficace des lignes en colonnes dans le serveur SQL
Je cherche un moyen efficace de convertir des lignes en colonnes dans un serveur SQL. J'ai entendu dire que PIVOT n'était pas très rapide et que je devais gérer beaucoup d'enregistrements.
Voici mon exemple:
-------------------------------
| Id | Value | ColumnName |
-------------------------------
| 1 | John | FirstName |
| 2 | 2.4 | Amount |
| 3 | ZH1E4A | PostalCode |
| 4 | Fork | LastName |
| 5 | 857685 | AccountNumber |
-------------------------------
Ceci est mon résultat:
---------------------------------------------------------------------
| FirstName |Amount| PostalCode | LastName | AccountNumber |
---------------------------------------------------------------------
| John | 2.4 | ZH1E4A | Fork | 857685 |
---------------------------------------------------------------------
Comment puis-je construire le résultat?
Il existe plusieurs manières de transformer des données de plusieurs lignes en colonnes. Dans SQL Server, vous pouvez utiliser la fonction PIVOT pour transformer les données de lignes en colonnes:
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;
Voir démo .
Si vous souhaitez transposer un nombre inconnu de columnnames, vous pouvez utiliser le code SQL dynamique:
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;
Voir démo .
Si vous ne souhaitez pas utiliser la fonction PIVOT, vous pouvez utiliser une fonction d'agrégat avec une expression 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
Voir démo .
Cela peut également être effectué à l'aide de plusieurs jointures, mais vous aurez besoin d'une colonne pour associer chacune des lignes que vous n'avez pas dans vos exemples de données. Mais la syntaxe de base serait la suivante:
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'
comme les données pivotantes sont toujours d'actualité, j'ai décidé d'ajouter quelque chose de nouveau. Il s’agit plutôt d’une méthode que d’un simple script mais qui vous offre beaucoup plus de possibilités. Tout d'abord, vous devez déployer 3 scripts: 1) Le type de table défini par l'utilisateur [ColumnActionList] -> conserve les données en tant que paramètre 2) SP [proc_PivotPrepare] -> prépare nos données 3) SP [proc_PivotExecute] -> exécuter le 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;
--#######################################################################################################################
À partir de l’exécution de la première requête (en passant le DB source et le nom de la table), vous obtiendrez une requête d’exécution pré-créée pour le second SP; il vous suffira de définir la colonne de votre source: + Stable + Valeur (sera utilisée). concentrer les valeurs en fonction de cela) + Dim (colonne que vous voulez utiliser pour faire pivoter)
Les noms et types de données seront définis automatiquement!
Je ne peux pas le recommander pour tous les environnements de production, mais fait le travail pour les requêtes de BI ad hoc.