在sql server中高效地将行转换为列
我正在寻找一种在SQL server中将行转换为列的有效方法，我听说PIVOT速度不是很快，我需要处理大量记录 这是我的例子：在sql server中高效地将行转换为列,sql,sql-server,sql-server-2008,pivot,Sql,Sql Server,Sql Server 2008,Pivot,我正在寻找一种在SQL server中将行转换为列的有效方法，我听说PIVOT速度不是很快，我需要处理大量记录 这是我的例子： ------------------------------- | Id | Value | ColumnName | ------------------------------- | 1 | John | FirstName | | 2 | 2.4 | Amount | | 3 | Z
-------------------------------
| Id | Value | ColumnName |
-------------------------------
| 1 | John | FirstName |
| 2 | 2.4 | Amount |
| 3 | ZH1E4A | PostalCode |
| 4 | Fork | LastName |
| 5 | 857685 | AccountNumber |
-------------------------------
---------------------------------------------------------------------
| FirstName |Amount| PostalCode | LastName | AccountNumber |
---------------------------------------------------------------------
| John | 2.4 | ZH1E4A | Fork | 857685 |
---------------------------------------------------------------------
如何生成结果？有几种方法可以将数据从多行转换为列 使用
PIVOTPIVOTselect Firstname, Amount, PostalCode, LastName, AccountNumber
from
(
select value, columnname
from yourtable
) d
pivot
(
max(value)
for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber)
) piv;
列名的轴
如果要转置的列名数目未知，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;
看
使用聚合函数
如果您不想使用PIVOT
函数，则可以使用带有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
使用多个联接
这也可以使用多个联接来完成，但是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'
这是一种方法，而不仅仅是一个脚本，但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
]->将数据保存为
参数
SP[proc\u PivotPrepare
]->准备我们的数据
SP[proc\u PivotExecute
]->执行脚本
将类型[dbo].[ColumnActionList]创建为表
(
[ID][smallint]不为空，
[ColumnName]nvarchar不为空，
[操作]nchar不为空
);
去
创建过程[dbo].[proc\u]
(
@DB_名称nvarchar（128），
@表名nvarchar（128）
)
作为
选择@DB\u Name=ISNULL（@DB\u Name，DB\u Name（））
声明@SQL\U代码nvarchar（最大值）
声明@MyTab表（ID smallint-identity（1,1），[Column_-Name]nvarchar（128），[Type]nchar（1），[Set-Action-SQL]nvarchar（max））；
选择@SQL\u Code='选择[]='''
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
+“全体联合”
+“选择“”----|声明用户定义类型[ID]/[ColumnName]/[PivotAction]”
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
+“全体联合”
+'选择''DECLARE@ColumnListWithActions ColumnActionList；''
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
+“全体联合”
+'选择“”----设置[PivotAction]（'''S''作为默认值）以选择维度和值''
+“全体联合”
+'选择'-|''
+“全体联合”
+'选择'----|''''S''''表示稳定列| |''D''''表示尺寸列| |'''V''''表示值列''
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
+“全体联合”
+“选择”“插入到带有操作值的@ColumnListWithActions（”“+CAST（按[名称]排序）上的行号（））中，作为nvarchar（10））+”、+“+”、+”、+“+”、+”；”
+'来自['+@DB_Name+'].sys.columns'
+'其中object_id=object_id（''['+@DB_Name+']..['+@TableName+']''）'
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
+“全体联合”
+“选择“”----|执行sp_PivotExecute，参数为：列和维度以及主表名称”
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
+“全体联合”
+'选择''EXEC[dbo].[sp_PivotExecute]@ColumnListWithActions'+'+'+@TableName+'+'''''''
+“全体联合”
+'选择'-------------------------------------------------------------------------------------''
执行SP_EXECUTESQL@SQL_代码；
去
创建过程[dbo]。[sp_PivotExecute]
(
@ColumnListWithActions列操作列表只读
，@TableName nvarchar（128）
)
作为
--#######################################################################################################################
--###|步骤1-将用户定义的表变量选择到临时表中
--#######################################################################################################################
如果对象_ID（'tempdb.dbo.#ColumnListWithActions，'U'）不为空，则删除表#ColumnListWithActions；
从@ColumnListWithActions中选择*进入#ColumnListWithActions；
--#############################################
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;
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