Returning customized results with SQL Server - sql

Question

This is a little complicated so I'm going to break it down. I'm trying to get results but couldn't figure out what the query is gonna look like. The premise is this, a users has purchased a specific set of items, their gear. When they go to my site, they see kits or setups that users have submitted. I want to only show them setups that have only the gear that they've purchased. They don't need to see setups with gear that they do not have. I hope this makes sense. Here's what my tables look like:
[Gear]
gearID is the unique key
has a list of all the gear (mics, heads, effects) with unique id's for each
[Kits]
kitID is the unique key
has a list of all the user submitted kits
[KitGearLink]
This table connects the [Kits] and [Gear] with each other. So this is the table that lists out what gear the user submitted kit has.
[Users]
userID is the unique key
list of all the users
[UserGear]
Links the [users] and [gear] table together. This is what stores what the user's personal gear consists of.
So how do I pull up records for each user that will show them all the kits that will work with the gear they have. If a kit has something the user doesn't own, then it won't show them. Any ideas?
Thanks guys!

Answer 1

Perhaps something like this:
SELECT *
FROM Kit k
WHERE k.KitID NOT IN (
SELECT DISTINCT kg.KitID
FROM KitGearLink kg
LEFT JOIN (
SELECT ug0.GearID
FROM UserGear ug0
WHERE ug0.UserID = #userParam
) ug ON kg.GearID = ug.GearID
WHERE ug.GearID = null
)
For a given user id the sub query return kits which fail the gear id join betwen user and kit (kits with a bit of gear the user doesn't have). This is used to filter the list of kits in the system.
Edit: Introduced second sub-query to filter user gear by user id parameter before the left join occurs, see comments.

Answer 2

Ok, you want a list of kits where all the gear in the kit has at some point been associated with a specific user. Best bet is to go through an SP and use a memory table. This assumes you are asking for kits for a specific user. you could get a complete list for all users, but more costly and complex....
DECLARE #UserId as int
SELECT #Userid = YOURUSER
Declare #tblUserKits TABLE (
UserId int null,
KitId int null,
GearId int null
)
-- GET ALL KITS THAT A USER HAS AT LEAST ONE PART OF
Insert Into #tbluserkits
select distinct u.userid, k.kitid, k.gearid
from usergear u
inner join Kitgearlink k on u.gearid = k.gearid
where u.Userid = #UserId
-- DELETE ALL KITS THAT THE USER IS MISSING A PART FOR
Delete from #tblUserKits WHERE KitId in
(select distinct t.kitid
from #tbluserkits t
inner join kitgearlink k on t.kitid = k.kitid
left outer join usergear u on k.gearid = u.gearid
WHERE u.gearid is null)
-- Finally return a list of kits
Select distinct KitId from #tblUserKits