Question

尝试从多个表中选择1个查询输出。只有让它与CROSS JOIN一起工作，输出虽然不是我想要实现的。它似乎从另一个表中按COLUMN迭代查询。

SELECT @SQLCmd = + 'bcp ' + 
                 '"SELECT ''<?xml version=""1.0"" encoding=""UTF-8""?>'' + ' + 
                 ' (SELECT ValID, ValSet, Id, Initials, firstname, lastname, email ' +
                 '  FROM Employees.dbo.IDCards CROSS JOIN Employees.dbo.Value' + 
                 ' WHERE CardID = 0 ' +
                 ' AND Value = 1 ' +
                 '  FOR XML PATH(''Employee''), ELEMENTS,  ROOT(''Employees'')) "' +
                 ' queryout '  +
           @FileName +
           ' -w -T -S' + @@SERVERNAME

输出就像这样。

- <Employees>
-   <Employee>
      <ValID>1</ValID> 
      <ValSet>Beach</ValSet>
      <id>4</id> 
      <Initials>JJ</Initials> 
      <Firstname>Jack</Firstname>
      <Lastname>Jack</Lastname>
      <email>JJ@testserver.com</email> 
    </Employee>
-   <Employee>
      <ValID>2</ValID> 
      <ValSet>Forrest</ValSet>
      <id>4</id> 
      <Initials>JJ</Initials> 
      <Firstname>Jack</Firstname>
      <Lastname>Jack</Lastname>
      <email>JJ@testserver.com</email> 
    </Employee>
- </Employees>

那么如果没有迭代的话，多个表中的一个SELECT怎么会这样？

更新我一直在尝试不同的东西。但这就是它现在看起来如何添加另一个表格。

IDCards

Id  | Initials  | firstname | lastname  | email
4   | JJ        | Jack      | Jack      | JJ@testserver.com
5   | MM        | Mike      | Mike      | MM@testserver.com

Value

ValID   |   ValSet  |
1       | Beach     |
2       | Forrest   |

CardData

CardID  | CardVal   |
4       | 1         |
5       | 1         |
5       | 2         |

如果有意义，我需要每个用户运行一次吗？

Answer 1

你的编辑会清除一些细节，但它仍然很模糊： - ）

我能想象的唯一关系（由于给定的值）就是这个。这是对的吗？

DECLARE @IDCards TABLE(Id INT,Initials VARCHAR(100),firstname VARCHAR(100),lastname VARCHAR(100),email VARCHAR(100));
INSERT INTO @IDCards VALUES
 (4,'JJ','Jack','Jack','JJ@testserver.com')
,(5,'MM','Mike','Mike','MM@testserver.com');

DECLARE @Value TABLE(ValID INT, ValSet VARCHAR(100));
INSERT INTO @Value VALUES
 (1,'Beach')
,(2,'Forrest');

DECLARE @CardData TABLE(CardID INT, CardVal INT);
INSERT INTO @CardData VALUES
 (4,1)
,(5,1)
,(5,2);

SELECT *
FROM @Value AS v
INNER JOIN @CardData AS cd ON v.ValID=cd.CardVal
INNER JOIN @IDCards AS ic ON cd.CardID=ic.Id

结果如下：

+-------+---------+--------+---------+----+----------+-----------+----------+-------------------+
| ValID | ValSet  | CardID | CardVal | Id | Initials | firstname | lastname | email             |
+-------+---------+--------+---------+----+----------+-----------+----------+-------------------+
| 1     | Beach   | 4      | 1       | 4  | JJ       | Jack      | Jack     | JJ@testserver.com |
+-------+---------+--------+---------+----+----------+-----------+----------+-------------------+
| 1     | Beach   | 5      | 1       | 5  | MM       | Mike      | Mike     | MM@testserver.com |
+-------+---------+--------+---------+----+----------+-----------+----------+-------------------+
| 2     | Forrest | 5      | 2       | 5  | MM       | Mike      | Mike     | MM@testserver.com |
+-------+---------+--------+---------+----+----------+-----------+----------+-------------------+

如果这是正确的，您可能会寻找这样的查询：

SELECT Id
      ,Initials
      ,firstname
      ,lastname
      ,email  
      ,(
        SELECT ValID
              ,ValSet
        FROM @CardData AS cd 
        INNER JOIN @Value AS v On cd.CardVal=v.ValID
        WHERE cd.CardID=ic.Id
        FOR XML PATH('Card'),TYPE
       )
FROM @IDCards AS ic
FOR XML PATH('Employee'),ROOT('Employees')

由于卡片为1:n，您需要将它们放在子选择中这是结果（在非常脏的水中钓鱼......）：

<Employees>
  <Employee>
    <Id>4</Id>
    <Initials>JJ</Initials>
    <firstname>Jack</firstname>
    <lastname>Jack</lastname>
    <email>JJ@testserver.com</email>
    <Card>
      <ValID>1</ValID>
      <ValSet>Beach</ValSet>
    </Card>
  </Employee>
  <Employee>
    <Id>5</Id>
    <Initials>MM</Initials>
    <firstname>Mike</firstname>
    <lastname>Mike</lastname>
    <email>MM@testserver.com</email>
    <Card>
      <ValID>1</ValID>
      <ValSet>Beach</ValSet>
    </Card>
    <Card>
      <ValID>2</ValID>
      <ValSet>Forrest</ValSet>
    </Card>
  </Employee>
</Employees>

Answer 2

使用UNION子句。

SELECT columns FROM table1
UNION
SELECT columns FROM table2

查询必须具有相同的列数

从多个表中选择而不进行迭代

2 个答案: