我的任务是想出一种翻译以下数据的方法:

date        category        amount
1/1/2012    ABC             1000.00
2/1/2012    DEF             500.00
2/1/2012    GHI             800.00
2/10/2012   DEF             700.00
3/1/2012    ABC             1100.00

分为以下几种:

date        ABC             DEF             GHI
1/1/2012    1000.00
2/1/2012                    500.00
2/1/2012                                    800.00
2/10/2012                   700.00
3/1/2012    1100.00

空白点可以是null,也可以是空白,任何一种都可以,类别需要是动态的。另一个可能的警告是,我们将以有限的容量运行查询,这意味着临时表将无法使用。我尝试过研究,并且已经登陆了PIVOT,但因为我以前从未使用过它,所以我真的不理解它,尽管我尽了最大的努力去弄清楚它。有人能告诉我正确的方向吗?


当前回答

Taryn的答案的一个版本的性能改进:

Data

CREATE TABLE dbo.Temp
(
    [date] datetime NOT NULL,
    category nchar(3) NOT NULL,
    amount money NOT NULL,

    INDEX [CX dbo.Temp date] CLUSTERED ([date]),
    INDEX [IX dbo.Temp category] NONCLUSTERED (category)
);

INSERT dbo.Temp
    ([date], category, amount)
VALUES
    ({D '2012-01-01'}, N'ABC', $1000.00),
    ({D '2012-01-02'}, N'DEF', $500.00),
    ({D '2012-01-02'}, N'GHI', $800.00),
    ({D '2012-02-10'}, N'DEF', $700.00),
    ({D '2012-03-01'}, N'ABC', $1100.00);

动态主

DECLARE 
    @Delimiter nvarchar(4000) = N',',
    @DelimiterLength bigint,
    @Columns nvarchar(max),
    @Query nvarchar(max);

SET @DelimiterLength = LEN(REPLACE(@Delimiter, SPACE(1), N'#'));

-- Before SQL Server 2017
SET @Columns =
    STUFF
    (
        (
            SELECT 
                [text()] = @Delimiter,
                [text()] = QUOTENAME(T.category)
            FROM dbo.Temp AS T
            WHERE T.category IS NOT NULL
            GROUP BY T.category
            ORDER BY T.category
            FOR XML PATH (''), TYPE
        )
        .value(N'text()[1]', N'nvarchar(max)'),
        1, @DelimiterLength, SPACE(0)
    );

-- Alternative for SQL Server 2017+ and database compatibility level 110+
SELECT @Columns = 
    STRING_AGG(CONVERT(nvarchar(max), QUOTENAME(T.category)), N',')
        WITHIN GROUP (ORDER BY T.category)
FROM 
(
    SELECT T2.category
    FROM dbo.Temp AS T2
    WHERE T2.category IS NOT NULL
    GROUP BY T2.category
) AS T;

IF @Columns IS NOT NULL
BEGIN
    SET @Query = 
        N'SELECT [date], ' + 
        @Columns + 
        N' 
        FROM
        (
            SELECT [date], amount, category
            FROM dbo.Temp
        ) AS S
        PIVOT
        (
            MAX(amount)
            FOR category IN (' +
            @Columns +
            N')
        ) AS P;';

    EXECUTE sys.sp_executesql @Query;
END;

执行计划

结果

date ABC DEF GHI
2012-01-01 00:00:00.000 1000.00 NULL NULL
2012-01-02 00:00:00.000 NULL 500.00 800.00
2012-02-10 00:00:00.000 NULL 700.00 NULL
2012-03-01 00:00:00.000 1100.00 NULL NULL

其他回答

这就是我的解决方案,清除不必要的空值

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

select @cols = STUFF((SELECT ',' + QUOTENAME(CodigoFormaPago) 
                from PO_FormasPago
                order by CodigoFormaPago
        FOR XML PATH(''), TYPE
        ).value('.', 'NVARCHAR(MAX)') 
    ,1,1,'')

select @maxcols = STUFF((SELECT ',MAX(' + QUOTENAME(CodigoFormaPago) + ') as ' + QUOTENAME(CodigoFormaPago)
                from PO_FormasPago
                order by CodigoFormaPago
        FOR XML PATH(''), TYPE
        ).value('.', 'NVARCHAR(MAX)')
    ,1,1,'')

set @query = 'SELECT CodigoProducto, DenominacionProducto, ' + @maxcols + '
            FROM
            (
                SELECT 
                CodigoProducto, DenominacionProducto,
                ' + @cols + ' from 
                 (
                    SELECT 
                        p.CodigoProducto as CodigoProducto,
                        p.DenominacionProducto as DenominacionProducto,
                        fpp.CantidadCuotas as CantidadCuotas,
                        fpp.IdFormaPago as IdFormaPago,
                        fp.CodigoFormaPago as CodigoFormaPago
                    FROM
                        PR_Producto p
                        LEFT JOIN PR_FormasPagoProducto fpp
                            ON fpp.IdProducto = p.IdProducto
                        LEFT JOIN PO_FormasPago fp
                            ON fpp.IdFormaPago = fp.IdFormaPago
                ) xp
                pivot 
                (
                    MAX(CantidadCuotas)
                    for CodigoFormaPago in (' + @cols + ')
                ) p 
            )  xx 
            GROUP BY CodigoProducto, DenominacionProducto'

t @query;

execute(@query);

Taryn的答案的一个版本的性能改进:

Data

CREATE TABLE dbo.Temp
(
    [date] datetime NOT NULL,
    category nchar(3) NOT NULL,
    amount money NOT NULL,

    INDEX [CX dbo.Temp date] CLUSTERED ([date]),
    INDEX [IX dbo.Temp category] NONCLUSTERED (category)
);

INSERT dbo.Temp
    ([date], category, amount)
VALUES
    ({D '2012-01-01'}, N'ABC', $1000.00),
    ({D '2012-01-02'}, N'DEF', $500.00),
    ({D '2012-01-02'}, N'GHI', $800.00),
    ({D '2012-02-10'}, N'DEF', $700.00),
    ({D '2012-03-01'}, N'ABC', $1100.00);

动态主

DECLARE 
    @Delimiter nvarchar(4000) = N',',
    @DelimiterLength bigint,
    @Columns nvarchar(max),
    @Query nvarchar(max);

SET @DelimiterLength = LEN(REPLACE(@Delimiter, SPACE(1), N'#'));

-- Before SQL Server 2017
SET @Columns =
    STUFF
    (
        (
            SELECT 
                [text()] = @Delimiter,
                [text()] = QUOTENAME(T.category)
            FROM dbo.Temp AS T
            WHERE T.category IS NOT NULL
            GROUP BY T.category
            ORDER BY T.category
            FOR XML PATH (''), TYPE
        )
        .value(N'text()[1]', N'nvarchar(max)'),
        1, @DelimiterLength, SPACE(0)
    );

-- Alternative for SQL Server 2017+ and database compatibility level 110+
SELECT @Columns = 
    STRING_AGG(CONVERT(nvarchar(max), QUOTENAME(T.category)), N',')
        WITHIN GROUP (ORDER BY T.category)
FROM 
(
    SELECT T2.category
    FROM dbo.Temp AS T2
    WHERE T2.category IS NOT NULL
    GROUP BY T2.category
) AS T;

IF @Columns IS NOT NULL
BEGIN
    SET @Query = 
        N'SELECT [date], ' + 
        @Columns + 
        N' 
        FROM
        (
            SELECT [date], amount, category
            FROM dbo.Temp
        ) AS S
        PIVOT
        (
            MAX(amount)
            FOR category IN (' +
            @Columns +
            N')
        ) AS P;';

    EXECUTE sys.sp_executesql @Query;
END;

执行计划

结果

date ABC DEF GHI
2012-01-01 00:00:00.000 1000.00 NULL NULL
2012-01-02 00:00:00.000 NULL 500.00 800.00
2012-02-10 00:00:00.000 NULL 700.00 NULL
2012-03-01 00:00:00.000 1100.00 NULL NULL

SQL Server 2017的更新版本使用STRING_AGG函数来构造主列列表:

create table temp
(
    date datetime,
    category varchar(3),
    amount money
);

insert into temp values ('20120101', 'ABC', 1000.00);
insert into temp values ('20120201', 'DEF', 500.00);
insert into temp values ('20120201', 'GHI', 800.00);
insert into temp values ('20120210', 'DEF', 700.00);
insert into temp values ('20120301', 'ABC', 1100.00);


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

SET @cols = (SELECT STRING_AGG(category,',') FROM (SELECT DISTINCT category FROM temp WHERE category IS NOT NULL)t);

set @query = 'SELECT date, ' + @cols + ' from 
            (
                select date
                    , amount
                    , category
                from temp
           ) x
            pivot 
            (
                 max(amount)
                for category in (' + @cols + ')
            ) p ';

execute(@query);

drop table temp;

下面的代码提供了将输出中的NULL替换为0的结果。

表创建和数据插入:

create table test_table
 (
 date nvarchar(10),
 category char(3),
 amount money
 )

 insert into test_table values ('1/1/2012','ABC',1000.00)
 insert into test_table values ('2/1/2012','DEF',500.00)
 insert into test_table values ('2/1/2012','GHI',800.00)
 insert into test_table values ('2/10/2012','DEF',700.00)
 insert into test_table values ('3/1/2012','ABC',1100.00)

查询以生成准确的结果,并将NULL替换为零:

DECLARE @DynamicPivotQuery AS NVARCHAR(MAX),
@PivotColumnNames AS NVARCHAR(MAX),
@PivotSelectColumnNames AS NVARCHAR(MAX)

--Get distinct values of the PIVOT Column
SELECT @PivotColumnNames= ISNULL(@PivotColumnNames + ',','')
+ QUOTENAME(category)
FROM (SELECT DISTINCT category FROM test_table) AS cat

--Get distinct values of the PIVOT Column with isnull
SELECT @PivotSelectColumnNames 
= ISNULL(@PivotSelectColumnNames + ',','')
+ 'ISNULL(' + QUOTENAME(category) + ', 0) AS '
+ QUOTENAME(category)
FROM (SELECT DISTINCT category FROM test_table) AS cat

--Prepare the PIVOT query using the dynamic 
SET @DynamicPivotQuery = 
N'SELECT date, ' + @PivotSelectColumnNames + '
FROM test_table
pivot(sum(amount) for category in (' + @PivotColumnNames + ')) as pvt';

--Execute the Dynamic Pivot Query
EXEC sp_executesql @DynamicPivotQuery

输出:

动态SQL PIVOT

创建列字符串的不同方法

create table #temp
(
    date datetime,
    category varchar(3),
    amount money
)

insert into #temp values ('1/1/2012', 'ABC', 1000.00)
insert into #temp values ('2/1/2012', 'DEF', 500.00)
insert into #temp values ('2/1/2012', 'GHI', 800.00)
insert into #temp values ('2/10/2012', 'DEF', 700.00)
insert into #temp values ('3/1/2012', 'ABC', 1100.00)

DECLARE @cols  AS NVARCHAR(MAX)='';
DECLARE @query AS NVARCHAR(MAX)='';

SELECT @cols = @cols + QUOTENAME(category) + ',' FROM (select distinct category from #temp ) as tmp
select @cols = substring(@cols, 0, len(@cols)) --trim "," at end

set @query = 
'SELECT * from 
(
    select date, amount, category from #temp
) src
pivot 
(
    max(amount) for category in (' + @cols + ')
) piv'

execute(@query)
drop table #temp

结果

date                    ABC     DEF     GHI
2012-01-01 00:00:00.000 1000.00 NULL    NULL
2012-02-01 00:00:00.000 NULL    500.00  800.00
2012-02-10 00:00:00.000 NULL    700.00  NULL
2012-03-01 00:00:00.000 1100.00 NULL    NULL