Querying based on a set of Named Attributes/Values

问题

I am working with a set of what is essentially Attribute/Value pairs (there's actually quite a bit more to this, but I'm simplifying for the sake of this question). Effectively you can think of the tables as such:

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

How would you query with SQL the set of EntityID,TargetID for which an Entity has all the attributes for a target as well as the corresponding value?

EDIT (DDL as requested):

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)
);

回答1:

Okay, I think after several tries and edits, this solution finally works:

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);

Test data:

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');

Test results:

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

To respond to your comment, here is a query with the tables reversed:

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);

And here's the output, given the same input data above.

+----------+----------+
| EntityID | TargetID |
+----------+----------+
|        1 |        1 |
|        3 |        3 |
|        5 |        1 |
+----------+----------+

回答2:

I like these kind of questions but I think it is not unreasonable to hope that the OP provides at least create scripts for the table(s) and maybe even some sample data.

I like to hear who agrees and who disagrees.

回答3:

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

回答4:

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
/

edit1:

If it is OK to have rows in the target table that have no match in the entities table, the solution simplifies to:

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
/

edit 2:

It is not easy to understand the exact requirements of the OP.

Here is a new select statement. I hope he will test all my select statements to understand the differences. I hope he has good test cases and knows what he wants.

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
/

来源：https://stackoverflow.com/questions/451856/querying-based-on-a-set-of-named-attributes-values

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