SQL Elaborate Joins Query - sql

Question

I'm trying to solve the below problem.
I feel like it is possible, but I can't seem to get it.
Here's the scenario:
Table 1 (Assets)
1 Asset-A
2 Asset-B
3 Asset-C
4 Asset-D
Table 2 (Attributes)
1 Asset-A Red
2 Asset-A Hard
3 Asset-B Red
4 Asset-B Hard
5 Asset-B Heavy
6 Asset-C Blue
7 Asset-C Hard
If I am looking for something having the same attributes as Asset-A, then it should identify Asset-B since Asset-B has all the same attributes as Asset-A (it should discard heavy, since Asset-A didn't specify anything different or the similar). Also, if I wanted the attributes for only Asset-A AND Asset-B that were common, how would I get that?
Seems simple, but I can't nail it...
The actual table I am using, is almost precisely Table2, simply an association of an AssetId, and an AttributeId so:
PK: Id
int: AssetId
int: AttributeId
I only included the idea of the asset table to simplify the question.

Answer 1

SELECT ato.id, ato.value
FROM (
SELECT id
FROM assets a
WHERE NOT EXISTS
(
SELECT NULL
FROM attributes ata
LEFT JOIN
attributes ato
ON ato.id = ata.id
AND ato.value = ata.value
WHERE ata.id = 1
AND ato.id IS NULL
)
) ao
JOIN attributes ato
ON ato.id = ao.id
JOIN attributes ata
ON ata.id = 1
AND ata.value = ato.value
, or in SQL Server 2005 (with sample data to check):
WITH assets AS
(
SELECT 1 AS id, 'A' AS name
UNION ALL
SELECT 2 AS id, 'B' AS name
UNION ALL
SELECT 3 AS id, 'C' AS name
UNION ALL
SELECT 4 AS id, 'D' AS name
),
attributes AS
(
SELECT 1 AS id, 'Red' AS value
UNION ALL
SELECT 1 AS id, 'Hard' AS value
UNION ALL
SELECT 2 AS id, 'Red' AS value
UNION ALL
SELECT 2 AS id, 'Hard' AS value
UNION ALL
SELECT 2 AS id, 'Heavy' AS value
UNION ALL
SELECT 3 AS id, 'Blue' AS value
UNION ALL
SELECT 3 AS id, 'Hard' AS value
)
SELECT ato.id, ato.value
FROM (
SELECT id
FROM assets a
WHERE a.id <> 1
AND NOT EXISTS
(
SELECT ata.value
FROM attributes ata
WHERE ata.id = 1
EXCEPT
SELECT ato.value
FROM attributes ato
WHERE ato.id = a.id
)
) ao
JOIN attributes ato
ON ato.id = ao.id
JOIN attributes ata
ON ata.id = 1
AND ata.value = ato.value

Answer 2

I don't completely understand the first part of your question, identifying assets based on their attributes.
Making some assumptions about column names, the following query would yield the common attributes between Asset-A and Asset-B:
SELECT [Table 2].Name
FROM [Table 2]
JOIN [Table 1] a ON a.ID = [Table 2].AssetID AND a.Name = 'Asset-A'
JOIN [Table 1] b ON b.ID = [Table 2].AssetID AND b.Name = 'Asset-B'
GROUP BY [Table 2].Name

Answer 3

Select * From Assets A
Where Exists
(Select * From Assets
Where AssetId <> A.AssetID
And (Select Count(*)
From Attributes At1 Join Attributes At2
On At1.AssetId <> At2.AssetId
And At1.attribute <> At2.Attribute
Where At1.AssetId = A.AssetId Asset) = 0 )
And AssetId = 'Asset-A'

Answer 4

select at2.asset, count(*)
from attribute at1
inner join attribute at2 on at1.value = at2.value
where at1.asset = "Asset-A"
and at2.asset != "Asset-A"
group by at2.asset
having count(*) = (select count(*) from attribute where asset = "Asset-A");

Answer 5

Find all assets who have every attribute that "A" has (but also may have additional attributes):
SELECT Other.ID
FROM Assets Other
WHERE
Other.AssetID <> 'Asset-A' -- do not return Asset A as a match to itself
AND NOT EXISTS (SELECT NULL FROM Attributes AttA WHERE
AttA.AssetID='Asset-A'
AND NOT EXISTS (SELECT NULL FROM Attributes AttOther WHERE
AttOther.AssetID=Other.ID AND AttOther.AttributeID = AttA.AttributeID
)
)
I.e., "find any asset where there is no attribute of A that is not also an attribute of this asset".
Find all assets who have exactly the same attributes as "A":
SELECT Other.ID
FROM Assets Other
WHERE
Other.AssetID <> 'Asset-A' -- do not return Asset A as a match to itself
AND NOT EXISTS (SELECT NULL FROM Attributes AttA WHERE
AttA.AssetID='Asset-A'
AND NOT EXISTS (SELECT NULL FROM Attributes AttOther WHERE
AttOther.AssetID=Other.ID
AND AttOther.AttributeID = AttA.AttributeID
)
)
AND NOT EXISTS (SELECT NULL FROM Attributes AttaOther WHERE
AttaOther.AssetID=Other.ID
AND NOT EXISTS (SELECT NULL FROM Attributes AttaA WHERE
AttaA.AssetID='Asset-A'
AND AttaA.AttributeID = AttaOther.AttributeID
)
)
I.e., "find any asset where there is no attribute of A that is not also an attribute of this asset, and where there is no attribute of this asset that is not also an attribute of A."

Answer 6

This solution works as prescribed, thanks for the input.
WITH Atts AS
(
SELECT
DISTINCT
at1.[Attribute]
FROM
Attribute at1
WHERE
at1.[Asset] = 'Asset-A'
)
SELECT
DISTINCT
Asset,
(
SELECT
COUNT(ta2.[Attribute])
FROM
Attribute ta2
INNER JOIN
Atts b
ON
b.[Attribute] = ta2.[attribute]
WHERE
ta2.[Asset] = ta.Asset
)
AS [Count]
FROM
Atts a
INNER JOIN
Attribute ta
ON
a.[Attribute] = ta.[Attribute]

Answer 7

Find all assets that have all the same attributes as asset-a:
select att2.Asset from attribute att1
inner join attribute att2 on att2.Attribute = att1.Attribute and att1.Asset <> att2.Asset
where att1.Asset = 'Asset-A'
group by att2.Asset, att1.Asset
having COUNT(*) = (select COUNT(*) from attribute where Asset=att1.Asset)

Answer 8

I thought maybe I can do this with LINQ and then work my way backwards with:
var result = from productsNotA in DevProducts
where productsNotA.Product != "A" &&
(
from productsA in DevProducts
where productsA.Product == "A"
select productsA.Attribute
).Except
(
from productOther in DevProducts
where productOther.Product == productsNotA.Product
select productOther.Attribute
).Single() == null
select new {productsNotA.Product};
result.Distinct()
I thought that translating this back to SQL with LinqPad would result into a pretty SQL query. However it didn't :). DevProducts is my testtable with a column Product and Attribute. I thought I'd post the LINQ query anyways, might be useful to people who are playing around with LINQ.
If you can optimize the LINQ query above, please let me know (it might result in better SQL ;))

Answer 9

I'm using following DDL
CREATE TABLE Attributes (
Asset VARCHAR(100)
, Name VARCHAR(100)
, UNIQUE(Asset, Name)
)
Second question is easy
SELECT Name
FROM Attributes
WHERE Name IN (SELECT Name FROM Attributes WHERE Asset = 'A')
AND Asset = 'B'
First question is not more difficult
SELECT Asset
FROM Attributes
WHERE Name IN (SELECT Name FROM Attributes WHERE Asset = 'A')
GROUP BY Asset
HAVING COUNT(*) = (SELECT COUNT(*) FROM FROM Attributes WHERE Asset = 'A')
Edit:
I left AND Asset != 'A' out of the WHERE clause of the second snippet for brevity