Question

我在SQL Server 2005中有一个包含两列Fruit和Color的表，如下所示

Fruit          Colour
Apple          Red
Orange         Red
Berry          Green
PineApple      Green

现在我想将其转换为邻接矩阵查询如下图所示

                Red        Green
Apple           1          0
Orange          1          0
Berry           0          1
PineApple       0          1

如果有水果和颜色，我想做的就是1 否则我想给0

Answer 1

以下是一个例子：

CREATE TABLE #Fruits (name varchar(10), color varchar(10))
GO

INSERT #Fruits VALUES ('Apple', 'Red')
INSERT #Fruits VALUES ('Orange', 'Red')
INSERT #Fruits VALUES ('Berry', 'Green')
INSERT #Fruits VALUES ('PineApple', 'Green')
GO

DECLARE @select_query nvarchar(4000);
DECLARE table_cursor CURSOR
  FOR SELECT DISTINCT color FROM #Fruits;
DECLARE @color varchar(10);

SET @select_query = N'SELECT name'

OPEN table_cursor;
FETCH NEXT FROM table_cursor INTO @color;

WHILE @@FETCH_STATUS = 0
BEGIN
  SET @select_query = @select_query + N', CASE WHEN color = ''' + @color + N''' THEN 1 ELSE 0 END AS ' + @color;
  FETCH NEXT FROM table_cursor INTO @color;
END
CLOSE table_cursor;
DEALLOCATE table_cursor;

SET @select_query = @select_query + N' FROM #Fruits';
EXEC sp_executesql @select_query

查找不同颜色
构建SELECT语句
通过sp_executesql

Answer 2

尝试动态Pivot。（我假设你的桌子的名字是t1）

像这样：

declare @sql nvarchar(max)
set @sql = ''

select  @sql = @sql +'['+Colour +'],'
from 
(select distinct colour from t1) t2

set @sql = substring(@sql,1,len(@sql) - 1)


set @sql = '
select * from(
select Fruit, Colour, 1 as CheckMark from t1
) as t2
pivot
(
SUM(CheckMark)
for Colour in ('+@sql+')
) as pivotTable'
execute (@sql)

此查询返回NULL而不是0。

希望我能帮助

Answer 3

SELECT Fruit,
   CASE WHEN Colour = 'Red' THEN 1 ELSE 0 END AS Red
   CASE WHEN Colour = 'Green' THEN 1 ELSE 0 END AS Green
FROM [TABLE_NAME]

Answer 4

很难避免数据透视中的那些空值。

declare @t table (fruit varchar(10), colour varchar(10))

insert @t
select 'Apple',     'Red'   union all
select 'Orange',    'Red'   union all
select 'Berry',     'Green' union all
select 'PineApple', 'Green'

select * from (
select a.fruit, b.colour, case when c.fruit is null then 0 else 1 end found from 
(select distinct fruit, colour from @t) a
cross join 
(select distinct colour from @t) b
left outer join 
(select distinct fruit, colour from @t) c
on a.fruit = c.fruit and b.colour = c.colour) d
PIVOT
(max(found)  
FOR colour
in([red],[green])  
)AS p
order by 3, 1

输出

fruit      red         green
---------- ----------- -----------
Apple      1           0
Orange     1           0
Berry      0           1
PineApple  0           1

Answer 5

CREATE TABLE #t(fruit VARCHAR(10), colour VARCHAR(10))

INSERT #t
SELECT 'Apple',     'Red'   UNION ALL
SELECT 'Orange',    'Red'   UNION ALL
SELECT 'Berry',     'Green' UNION ALL
SELECT 'PineApple', 'Green'


DECLARE @pivot_columns VARCHAR(2000)
SET @pivot_columns = ''

SELECT @pivot_columns =  @pivot_columns +  '[' + colour + '],'
FROM (SELECT DISTINCT colour FROM #t)t

SET @pivot_columns = LEFT(@pivot_columns, LEN(@pivot_columns) - 1)

PRINT @pivot_columns

DECLARE @sql VARCHAR(MAX)

SET @sql = '
    SELECT fruit, ' + @pivot_columns + '
    FROM
    (
        SELECT fruit, colour
        FROM #t
    ) AS SourceTable
    PIVOT
    (
    COUNT(colour)
    FOR Colour IN (' + @pivot_columns + ')
    ) AS PivotTable'

PRINT @sql

EXEC (@sql)

DROP TABLE #t

Answer 6

有可能保持Maziar Taheri的回答的动态性并摆脱零点：

if object_id('tempdb..#t') is not null
    drop table #t
create table #t (fruit varchar(10), colour varchar(10))
insert #t
select 'Apple',     'Red'   union all
select 'Apple',     'Green'   union all
select 'Apple',     'Yellow'   union all
select 'Apple',     'Yellow'   union all
select 'Orange',    'Red'   union all
select 'Orange',    'Yellow'   union all
select 'Berry',     'Green' union all
select 'Berry',     'Red' union all
select 'Berry',     'Black' union all
select 'PineApple', 'Green'
declare @sql nvarchar(max), @colours nvarchar(max)
select @sql = '', @colours = ''
select  @colours = @colours +'['+Colour +'],',
        @sql = @sql +'isnull(['+Colour+'],0) '+Colour+','
from 
(select distinct colour from #t) t2
set @colours = substring(@colours,1,len(@colours) - 1)
set @sql = substring(@sql,1,len(@sql) - 1)
select @sql = '
select Fruit,'+@sql +' from
(
select Fruit, Colour, 1 as CheckMark from #t
) as t2
pivot
(
SUM(CheckMark)
for Colour in ('+@colours+')
) as pivotTable'
execute (@sql)

如何将两个列表转换为邻接矩阵SQL Server T-SQL？

6 个答案: