SQL 连接包含维度的表

Question

如何连接表 1 和表 2（包含维度及其值）以获得以下结果：

更新感谢您提出使用 PIVOT 的方式。只是出于好奇 - 是否可以通过多个左连接来解决它？

更新 2 我想与您分享我解决几个左连接问题的想法。它非常简单并且比 Pivot 方式快得多。您可以在下面找到我的答案。

Answer 1

declare @table1 table
(
    id int, 
    salary int
)

insert into @table1
values 
(1, 1000),
(2, 2000)

declare @table2 table
(
    id int, 
    dimension varchar(1000),
    dimensionValue varchar(1000)
)

insert into @table2 
values
(1, 'eyes','blue'),
(1, 'sex','male'),
(1, 'worker type','marvelous'),
(2, 'eyes','brown'),
(2, 'sex', 'female'),
(2, 'worker type','spectacular')

使用数据透视查询

SELECT t2.*, t1.salary
FROM
@table1 t1 
join 
    (SELECT * FROM @table2) AS SourceTable
    PIVOT
    (
        max(dimensionValue)
        FOR dimension IN ([eyes],[worker type],[sex])
    ) AS T2 
on T2.id = t1.id

Answer 2

试试下面的代码：

WITH PivotTable2 AS
(
    SELECT ID, SEX, EYES, [WORKER TYPE]
    FROM (
    SELECT ID, DIMENSION, [DIMENSION VALUE]
    FROM Table2) up
    PIVOT (MAX([DIMENSION VALUE]) FOR DIMENSION IN (SEX, EYES, [WORKER TYPE])) AS pvt
)
SELECT T1.ID,T1.Salary,T2.SEX,T2.EYES,T2.[WORKER TYPE]
FROM Table1 AS T1
LEFT JOIN PivotTable2 T2 ON T1.ID=T2.ID

希望对您有所帮助！

Answer 3

使用左连接：

CREATE TABLE #Table1
(
    ID int, 
    Salary int
)

INSERT INTO #Table1
VALUES 
(1, 1000),
(2, 2000)

CREATE TABLE #Table2
(
    ID int, 
    Dimension varchar(1000),
    DimensionValue varchar(1000)
)

INSERT INTO #Table2 
VALUES
(1, 'eyes','blue'),
(1, 'sex','male'),
(1, 'worker type','marvelous'),
(2, 'eyes','brown'),
(2, 'sex', 'female'),
(2, 'worker type','spectacular')


SELECT T1.ID,S.Sex,E.Eyes,WT.[Worker Type]
FROM #Table1 AS T1
LEFT JOIN
(   SELECT  ID,
            DimensionValue AS Sex
    FROM #Table2
    WHERE Dimension='sex'
) S ON T1.ID=S.ID
LEFT JOIN
(   SELECT  ID,
            DimensionValue AS Eyes
    FROM #Table2
    WHERE Dimension='eyes'
) E ON T1.ID=E.ID
LEFT JOIN
(   SELECT  ID,
            DimensionValue AS [Worker Type]
    FROM #Table2
    WHERE Dimension='worker type'
) WT ON T1.ID=WT.ID

DROP TABLE #Table1,#Table2

必须提到每个维度的左连接..!!

Answer 4

我的经验得出了这段代码，我想与您分享。关键是每次我们进行左连接时都为维度 table 分配新的别名。

SELECT 
    T1.ID
    ,S.DimensionValue AS Sex
    ,E.DimensionValue AS Eyes
    ,WT.DimensionValue AS [Worker Type]
FROM #Table1 AS T1

LEFT JOIN #Table2 AS S  -- new alias here for dimension table
ON T1.ID=S.ID AND S.Dimension='sex'
LEFT JOIN #Table2 AS E  -- new alias here for dimension table
ON T1.ID=E.ID AND E.Dimension='eyes'
LEFT JOIN #Table2 AS WT -- new alias here for dimension table
ON T1.ID=WT.ID AND WT.Dimension='worker type'

SQL 连接包含维度的表

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sql-server-2012