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我正在使用一组本质上是属性/值对的东西（实际上还有很多，但为了这个问题，我正在简化）。实际上，您可以这样考虑表：

实体 (EntityID,AttributeName,AttributeValue) PK=EntityID,AttributeName
Targets (TargetID,AttributeName,AttributeValue) PK=TargetID,AttributeName

您将如何使用 SQL 查询 EntityID、TargetID 的集合，其中一个实体具有目标的所有属性以及相应的值？

编辑（根据要求进行 DDL）：

CREATE TABLE Entities(
    EntityID INTEGER NOT NULL,
    AttributeName CHAR(50) NOT NULL,
    AttributeValue CHAR(50) NOT NULL,
    CONSTRAINT EntitiesPK PRIMARY KEY (EntityID,AttributeName)
);
CREATE TABLE Targets(
    TargetID INTEGER NOT NULL,
    AttributeName CHAR(50) NOT NULL,
    AttributeValue CHAR(50) NOT NULL,
    CONSTRAINT TargetsPK PRIMARY KEY (TargetID,AttributeName)
);
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4 回答 4

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我喜欢这类问题，但我认为希望 OP 至少为表提供创建脚本，甚至可能提供一些示例数据并不是不合理的。

我喜欢听谁同意谁不同意。

于 2009-01-16T20:38:39.813 回答
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好的，我认为经过几次尝试和编辑，这个解决方案终于奏效了：

SELECT e1.EntityID, t1.TargetID
FROM Entities e1
  JOIN Entities e2 ON (e1.EntityID = e2.EntityID)
  CROSS JOIN Targets t1
  LEFT OUTER JOIN Targets t2 ON (t1.TargetID = t2.TargetID
    AND e2.AttributeName = t2.AttributeName
    AND e2.AttributeValue = t2.AttributeValue)
GROUP BY e1.EntityID, t1.TargetID
HAVING COUNT(e2.AttributeValue) = COUNT(t2.AttributeValue);

测试数据：

INSERT INTO Entities VALUES 
 -- exact same attributes, should match
 (1, 'Foo1', '123'),
 (1, 'Bar1', '123'),
 -- same attributes but different values, should not match
 (2, 'Foo2', '456'),
 (2, 'Bar2', '456'),
 -- more columns in Entities, should not match
 (3, 'Foo3', '789'),
 (3, 'Bar3', '789'),
 (3, 'Baz3', '789'),
 -- fewer columns in Entities, should match
 (4, 'Foo4', '012'),
 (4, 'Bar4', '012'),
 -- same as case 1, should match Target 1
 (5, 'Foo1', '123'),
 (5, 'Bar1', '123'),
 -- one attribute with different value, should not match
 (6, 'A', 'one'),
 (6, 'B', 'two');

INSERT INTO Targets VALUES 
 (1, 'Foo1', '123'),
 (1, 'Bar1', '123'),
 (2, 'Foo2', 'abc'),
 (2, 'Bar2', 'abc'),
 (3, 'Foo3', '789'),
 (3, 'Bar3', '789'),
 (4, 'Foo4', '012'),
 (4, 'Bar4', '012'),
 (4, 'Baz4', '012'),
 (6, 'A', 'one'),
 (6, 'B', 'twox');

测试结果：

+----------+----------+
| EntityID | TargetID |
+----------+----------+
|        1 |        1 | 
|        4 |        4 | 
|        5 |        1 | 
+----------+----------+

为了回复您的评论，这里是一个颠倒表格的查询：

SELECT e1.EntityID, t1.TargetID
FROM Targets t1
  JOIN Targets t2 ON (t1.TargetID = t2.TargetID)
  CROSS JOIN Entities e1
  LEFT OUTER JOIN Entities e2 ON (e1.EntityID = e2.EntityID
    AND t2.AttributeName = e2.AttributeName
    AND t2.AttributeValue = e2.AttributeValue)
GROUP BY e1.EntityID, t1.TargetID
HAVING COUNT(e2.AttributeValue) = COUNT(t2.AttributeValue);

这是输出，给定上面相同的输入数据。

+----------+----------+
| EntityID | TargetID |
+----------+----------+
|        1 |        1 |
|        3 |        3 |
|        5 |        1 |
+----------+----------+
于 2009-01-16T21:11:47.953 回答
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SELECT  *
FROM    (
    SELECT  eo.total,
        (
        SELECT  COUNT(*)
        FROM    Entities e, Targets t
        WHERE   e.EntityID = eo.EntityID
            AND t.TargetID = e.EntityID
            AND t.AttributeName = e.AttributeName
            AND t.AttributeValue = e.AttributeValue
        ) AS equal
    FROM    (
        SELECT  e.EntityID, COUNT(*) as total
        FROM    Entities e
        GROUP BY
            e.EntityID
        ) eo
    )
WHERE   total = equal
于 2009-01-16T21:18:47.627 回答
0 
select distinct entityid,targetid
from   entities ent
,      targets  tar
where  not exists  
       (  select attributename, AttributeValue 
          from   targets  tar2
          where  tar.targetid = tar2.targetid
          minus
          select attributename, AttributeValue 
          from   entities  ent2
          where  ent2.entityid = ent.entityid)
and    not exists  
       (  select attributename, AttributeValue 
          from   entities  ent2
          where  ent2.entityid = ent.entityid
          minus 
          select attributename, AttributeValue 
          from   targets  tar2
          where  tar.targetid = tar2.targetid)
order by entityid,targetid
/

编辑1：

如果目标表中的行在实体表中没有匹配项是可以的，则解决方案简化为：

select distinct entityid,targetid
from   entities ent
,      targets  tar
where  not exists  
       (  select attributename, AttributeValue 
          from   entities  ent2
          where  ent2.entityid = ent.entityid
          minus 
          select attributename, AttributeValue 
          from   targets  tar2
          where  tar.targetid = tar2.targetid)
order by entityid,targetid
/

编辑2：

理解 OP 的确切要求并不容易。

这是一个新的选择语句。我希望他会测试我所有的选择语句以了解差异。我希望他有好的测试用例并且知道他想要什么。

select distinct entityid,targetid
from   entities ent
,      targets  tar
where  not exists  
       (  select attributename, AttributeValue 
          from   targets  tar2
          where  tar.targetid = tar2.targetid
          minus  
          select attributename, AttributeValue 
          from   entities  ent2
          where  ent2.entityid = ent.entityid)
order by entityid,targetid
/
于 2009-01-16T21:22:20.413 回答