subquery returning more than one value - sql

Question

SELECT CG.SITEID,
CR.COLLECTIONID,
CG.COLLECTIONNAME,
CASE
WHEN CR.ARCHITECTUREKEY = 5
THEN
N'vSMS_R_System'
WHEN CR.ARCHITECTUREKEY = 0
THEN
(SELECT BASETABLENAME
FROM DISCOVERYARCHITECTURES
JOIN
COLLECTION_RULES
ON DISCOVERYARCHITECTURES.DISCARCHKEY =
COLLECTION_RULES.ARCHITECTUREKEY
JOIN
COLLECTIONS_G
ON COLLECTION_RULES.COLLECTIONID =
COLLECTIONS_G.COLLECTIONID
WHERE COLLECTIONS_G.SITEID = (SELECT TOP 1 SOURCECOLLECTIONID FROM VCOLLECTIONDEPENDENCYCHAIN WHERE DEPENDENTCOLLECTIONID = CG.SITEID ORDER BY LEVEL DESC))
ELSE (SELECT DA.BASETABLENAME FROM DISCOVERYARCHITECTURES DA WHERE DA.DISCARCHKEY=CR.ARCHITECTUREKEY) END AS TABLENAME
FROM COLLECTIONS_G CG
JOIN COLLECTIONS_L CL ON CG.COLLECTIONID=CL.COLLECTIONID
JOIN COLLECTION_RULES CR ON CG.COLLECTIONID=CR.COLLECTIONID
WHERE (CG.FLAGS&4)=4 AND CL.CURRENTSTATUS!=5
I am having a problem with the code above, around the line:
when cr.ArchitectureKey=0 then...
The problem is that the sub-query returns more than one value, and I'm not too sure how to invert the query so that I get rid of the error.
To make matters worse, cr.ArchitectureKey would normally join with da.DiscArchKey, but while cr.ArchitectureKey can have a value of 0, that does not exist in da.DiscArchKey, meaning if I join the two directly I lose data.
EDIT
More information regarding the problem itself:
This is a stored procedure for a Microsoft product that has a 'bug' (probably considered a feature though) which I'm trying to fix. Don't worry, this is only in my own little test server.
Anyway, there's the concept of a Collection. All Collections must have a parent (determined through VCOLLECTIONDEPENDENCYCHAIN), with the exception of the very top level Collection that is a system collection and cannot be modified.
Each collection can have 0 or more rules, and each rule has a rule type, where the ID of the rule type is saved onto COLLECTION_RULES and the matching string for that ID is saved onto DISCOVERYARCHITECTURES.
In most cases, a rule is a WQL query, and the rule type is determined by what tables are queried on the WQL query.
However, and this is where the problem lies, collections can also have a query of type 'include' or 'exclude', which basically forces it to borrow the query of another Collection. So effectively you include the results of another Collection's query onto your own Collection, and that's the query.
As far as COLLECTION_RULES is concerned, when that happens, the ID of the rule type is 0, which is a value that doesn't exist in DISCOVERYARCHITECTURES.
What I was trying to modify was so that when the rule type is 0, get and use the rule type(s) of the highest up parent (not the direct parent since the parent Collection could also have a single include rule, in which case the rule type would still be 0).
The problem is that because each rule can have multiple rule types, it returns multiple rows in some instances.
I tried to invert the query to remove the SELECT and use joins only, but failed because I found I always needed to join it to DISCOVERYARCHITECTURES and I have nothing to join it on when the rule type = 0.
EDIT2
Sample data:
Collections_G
Collections_L
Collection_Rules
DiscoveryArchitectures
vCollectionDependencyChain
Original Query and Original Results
SELECT cg.SiteID,
CASE
WHEN da.DiscArchKey=5
THEN N'vSMS_R_System'
ELSE da.BaseTableName END AS TableName
FROM Collections_G cg
JOIN Collections_L cl ON cg.CollectionID=cl.CollectionID
JOIN Collection_Rules cr ON cg.CollectionID=cr.CollectionID
JOIN DiscoveryArchitectures da ON cr.ArchitectureKey=da.DiscArchKey
WHERE (cg.Flags&4)=4 AND cl.CurrentStatus!=5
As you can see from the results picture above, some collections appear multiple times but with different TableNames. This is because each collection have have several rules, and each rule has one cr.ArchitectureKey
Also, and more importantly, collections PS10000B and PS10000C do not show up because their cr.ArchitectureKey = 0 which is a value that doesn't exist in da.DiscArchKey.
My goal is to have collections that have a cr.ArchitectureKey appear, but I need to assign them a cr.ArchitectureKey
My thought (which is slightly flawed, but don't know enough SQL to make it better, so if someone could help with that it would be appreciated too) was to get use the da.DiscArchKey from the top level parent. But the top level parent can have multiple DiscArchKeys, which is what is causing the problem.
As mentioned above getting the top level parent is slightly flawed, and ideally I would get the top level cr.ReferencedCollectionID. In other words, if PS10000B has a cr.ReferencedCollectionID of PS10000C and PS10000C has a cr.ReferencedCollectionID of SMS00002 but because SMS00002 has no cr.ReferencedCollectionID then SMS00002 is the top level cr.ReferencedCollectionID and both PS10000B and PS10000C should have da.DiscArchKey(s) equal to those of SMS00002.

Answer 1

Please have a look at a wired solution that comes into mind. You may face some syntax errors(most probably in 2nd and 3rd CTE) but it just an idea.
Get each case values in separate CTEs and then combine them at the end.
;WITH CTE
AS
(
SELECT CG.SITEID,
CR.COLLECTIONID,
CG.COLLECTIONNAME
FROM COLLECTIONS_G CG
JOIN COLLECTIONS_L CL ON CG.COLLECTIONID=CL.COLLECTIONID
JOIN COLLECTION_RULES CR ON CG.COLLECTIONID=CR.COLLECTIONID
WHERE (CG.FLAGS&4)=4 AND CL.CURRENTSTATUS!=5
),
ARCHITECTUREKEY5
AS
(
SELECT C.SITEID,
C.COLLECTIONID,
C.COLLECTIONNAME,
N'vSMS_R_System' as TABLENAME
FROM CTE C WHERE C.ARCHITECTUREKEY = 5
),
ARCHITECTUREKEY0
AS
(
SELECT C.SITEID,
C.COLLECTIONID,
C.COLLECTIONNAME,
BASETABLENAME as TABLENAME
FROM CTE C,
DISCOVERYARCHITECTURES
JOIN
COLLECTION_RULES
ON DISCOVERYARCHITECTURES.DISCARCHKEY =
COLLECTION_RULES.ARCHITECTUREKEY
JOIN
COLLECTIONS_G
ON COLLECTION_RULES.COLLECTIONID =
COLLECTIONS_G.COLLECTIONID
WHERE COLLECTIONS_G.SITEID = (SELECT TOP 1 SOURCECOLLECTIONID FROM VCOLLECTIONDEPENDENCYCHAIN WHERE DEPENDENTCOLLECTIONID = C.SITEID ORDER BY LEVEL DESC))
and C.ARCHITECTUREKEY = 0
),
ARCHITECTUREKEYOTHER
AS
(
SELECT C.SITEID,
C.COLLECTIONID,
C.COLLECTIONNAME,
DA.BASETABLENAME as TABLENAME
FROM DISCOVERYARCHITECTURES DA, CTE C WHERE DA.DISCARCHKEY=CR.ARCHITECTUREKEY AND C.ARCHITECTUREKEY not in (0,1)
)
Select * from ARCHITECTUREKEY5
UNION
Select * from ARCHITECTUREKEY0
UNION
Select * from ARCHITECTUREKEYOTHER