Question

我有三张桌子：

    __Person__                 __Hat__           __Shoe__ 
 ID          int             ID    int         ID     int
 Name        nvarchar        Name  nvarchar    Name   nvarchar
 HatID       int
 ShoeID      int

以下是表格的一些示例数据：

________________Person_________________
-ID-   -Name-   -HatID-  -ShoeID-
1      Anna        1        2
2      Nina        2        3
3      Lola        3       NULL

______Hat_______
-ID-   -Name-
1       Blue
2       Red
3       Green

______Shoe_______
-ID-   -Name-
1       Boot
2       Heels
3       Sport

我有这样的查询：

SELECT Person.ID, Person.Name, Hat.Name, Shoe.Name
FROM   Person
INNER JOIN Hat  ON Person.HatID = Hat.ID
JOIN  JOIN Shoe ON Person.Shoe  = Shoe.ID

此查询返回以下结果：

-PersonID-   -PersonName-   -HatName-     -ShoeName-
  1           Anna             Blue          Heels
  2           Nina             Red           Sport
  3           Lola             Green         NULL

我想提供PersonName，HatName和ShoeName订单号1, 2, 3。我需要这样的结果：

-PersonID-    -OrderNumber-    -Value-
  1             1               Anna
  1             2               Blue
  1             3               Heels
  2             1               Nina
  2             2               Red
  2             3               Sport
  3             1               Lola
  3             2               Green
  3             3               NULL

我应该如何编写查询以返回此结果？

Answer 1

试试这个：

SELECT Person.ID, 1 OrderNumber, Person.Name
FROM   Person
UNION ALL
SELECT Person.ID, 2 OrderNumber, Hat.Name
FROM   Person 
LEFT JOIN JOIN Hat  ON Person.HatID = Hat.ID
UNION ALL
SELECT Person.ID, 3 OrderNumber, Shoe.Name
FROM   Person 
LEFT JOIN JOIN Shoe ON Person.ShoeID = Shoe.ID
ORDER BY 1,2

Answer 2

您可以在此处使用UNPIVOT：

DECLARE @Persons TABLE
    (
      ID INT ,
      Name NVARCHAR(20) ,
      HatID INT ,
      ShoeID INT
    )
DECLARE @Hats TABLE ( ID INT, Name NVARCHAR(20) )
DECLARE @Shoes TABLE ( ID INT, Name NVARCHAR(20) )

INSERT  INTO @Persons
VALUES  ( 1, 'Anna', 1, 2 ),
        ( 2, 'Nina', 2, 3 ),
        ( 3, 'Lola', 3, NULL )

INSERT  INTO @Hats
VALUES  ( 1, 'Blue' ),
        ( 2, 'Red' ),
        ( 3, 'Green' )

INSERT  INTO @Shoes
VALUES  ( 1, 'Boot' ),
        ( 2, 'Heels' ),
        ( 3, 'Sport' );
WITH    cte
          AS ( SELECT   p.ID ,
                        p.Name AS PersonName ,
                        h.Name AS HatName ,
                        ISNULL(s.Name, '') AS ShoeName
               FROM     @Persons p
                        INNER JOIN @Hats h ON p.HatID = h.ID
                        LEFT  JOIN @Shoes s ON p.ShoeID = s.ID
             )
    SELECT  ID AS PersonID ,
            ROW_NUMBER() OVER ( PARTITION BY ID ORDER BY ( SELECT
                                                              1
                                                         ) ) AS OrderNumber ,
            IIF(Value = '', NULL, Value) AS Value
    FROM    cte UNPIVOT( Value FOR v IN ( [PersonName], [HatName], [ShoeName] ) ) u;

输出：

PersonID    OrderNumber Value
1           1           Anna
1           2           Blue
1           3           Heels
2           1           Nina
2           2           Red
2           3           Sport
3           1           Lola
3           2           Green
3           3           NULL

SQL查询对话

2 个答案: