Using Count() and Sum() correctly in SQL? - sql

Question

Ok, so I hope I can explain this question well enough, because I feel like this is going to be a tough one.
I have two tables I'm working with today. These look like:
#pset table (PersonID int, SystemID int, EntitlementID int, TargetID int)
#Connector table (TargetName varchar(10), fConnector bit)
The first table stores records that tell me, oh this person has this system, which is composed of these entitlements, whom have these targets. A little complicated, but stay with me. The second stores the TargetName and then whether or not that target has a connector in my not-so-theoretical system.
What I'm trying to do is merge these two tables so that I can see the target flag for each row in #pset. This will help me later as you'll see.
If each entitlement in a system has a connector to the target (the flag is true for all of them), then I'd like to know.
All the others should go into a different table.
This is what I tried to do, but it didn't work. I need to know where I went wrong. Hopefully someone with more experience than me will be able to answer.
-- If the count(123) = 10 (ten rows with SystemID = 123) and the sum = 10, cool.
select pset.*, conn.fConnector from #pset pset
inner join vuTargets vt
on vt.TargetID = pset.TargetID
inner join #conn conn
on conn.TargetName = vt.TargetName
group by ProfileID, SystemRoleID, EntitlementID, TargetID, fConnector
having count(SystemID) = sum(cast(fConnector as int))
order by ProfileID
and
-- If the count(123) = 10 (ten rows with SystemID = 123) and the sum <> 10
select pset.*, conn.fConnector from #pset pset
inner join vuTargets vt
on vt.TargetID = pset.TargetID
inner join #conn conn
on conn.TargetName = vt.TargetName
group by ProfileID, SystemRoleID, EntitlementID, TargetID, fConnector
having count(SystemID) <> sum(cast(fConnector as int))
order by ProfileID
Unfortunately, these do not work :(
Edit
Here is a screenshot showing the problem. Notice ProfileID 1599 has a SystemID of 1126567, but one of the entitlements doesn't have a connector! How can I get both of these rows into the second query? (above)

Answer 1

Your basic problem is that you're trying to roll up to two different record sets.
The initial set (the SELECT and GROUP BY clauses) is saying that you want one record for every difference in the set [ProfileId, SystemId, EntitlementId, TargetId, fConnector].
The second set (the HAVING clause) is saying that you want, for every row in the inital set, to compare it's COUNT of records with the SUM of the connections. However, because you've asked for grouping down to the individual flag, this has the effect of getting a single row for each flag (assuming 1-to-1 relationships). Effectively, you're saying - 'Hey, if this target has a connection? Yeah, I want it'.
What you appear to want is a roll up to the SystemId value. To do that, you will need to change your SELECT and GROUP BY clauses to only include the set [ProfileId, SystemId]. This will return only those rows (keyed from profile and system) who has all targets 'connected'. You will not be able to see the individual entitlements, targets, and whether they are connected (you will be able to infer that they will all be/not be connected, however).
EDIT:
In the interests of full disclosure, here is how you'd get something similar to your original results set, where it lists all EntitlementIds and TargetIds:
WITH all_connections as (SELECT pset.ProfileId, pset.SystemRoleId
FROM #pset pset
INNER JOIN vuTargets vt
ON vt.TargetId = pset.TargetId
INNER JOIN #conn conn
ON conn.TargetName = vt.TargetName
GROUP BY pset.ProfileId, pset.SystemRoleId
HAVING COUNT(pset.SystemRoleId)
= SUM(CAST(fConnector as INT)))
SELECT pset.*
FROM #pset pset
JOIN all_connections conn
ON conn.ProfileId = pset.ProfileId
AND conn.SystemRoleId = pset.SystemRoleId
This should get you a listing, down to the TargetId, of ProfileId/SystemRoleId keys where all EntitlementIds and TargetIds have a connection (or, flip the CTE = to <> for those where not all do).

Answer 2

Edit: fixed my original queries, updated the description as well
You can split this up: first find the TargetIDs that have an fConnector of 0. Then find the PersonID, SystemID pairs that have any target equal to the ones you found. Then select the relevant data: (this finds the PersonID, SystemID pair where at least one entitlement does not have a connector to the target)
with abc as (
select PersonID, SystemID
from pset P
where TargetID in (
select TargetID
from vuTargets V join connector C on V.TargetName = C.TargetName
where C.fConnector = 0
)
)
select P.PersonID, P.SystemID, P.EntitlementID, P.TargetID, C.fConnector
from pset P
join abc on ((P.PersonID = abc.PersonID) and (P.SystemID = abc.SystemID))
join vuTargets V on P.TargetID = V.TargetID
join connector C on V.TargetName = C.TargetName
The query to find the PersonID, SystemID pairs where all entitlements have a connector to the target is similar:
with abc as (
select PersonID, SystemID
from pset P
where TargetID in (
select TargetID
from vuTargets V join connector C on V.TargetName = C.TargetName
where C.fConnector = 0
)
)
select P.PersonID, P.SystemID, P.EntitlementID, P.TargetID, C.fConnector
from
pset P
join abc on ((P.PersonID <> abc.PersonID) or (P.SystemID <> abc.SystemID))
join vuTargets V on P.TargetID = V.TargetID
join connector C on V.TargetName = C.TargetName
The difference is in the join with the temp table (<> vs =). This is very similar to zero's answer, but doesn't use counts or sums.