SQL Query to retrieve data while excluding a set of rows - sql

Question

I have basically four tables (SQL Server):
Objects:
id
ObjectName
Components
id
ComponentName
ObjectsDetails:
ObjectID
ComponentID
ExclusionTable
id
ComponentID
Basically, these tables describe Objects and what Objects are made of (what components)
For example, Object "A" may be made out of component "A" and component "B".
In this case, the tables would be populated this way:
Objects:
id ObjectName
1 A
Components:
id ComponentName
1 A
2 B
ObjectDetails:
ObjectID ComponentID
1 1
1 2
Now, "ExclusionTable" may have a list of components that are to be excluded from a search (therefore, excluding entire objects if the object is made out of at least one of those components).
For example, I would like to ask:
"Give me all the Objects that are not made out of components A and B".
Therefore, my question is:
Is there a way to write a query for that ? No views, no stored procedures please.. my SQL engine does not support that.
I tried something like:
SELECT DISTINCT ObjectName FROM Objects INNER JOIN ObjectsDetails ON Objects.id =
ObjectDetails.ObjectID WHERE ObjectsDetails.ComponentID NOT IN (1,2)
in case ExclusionTable tells us that Components A and B needs to be excluded.
Of course, that doesn't work...
I tried a few variations using WHERE NOT EXISTS (SELECT * FROM ExclusionTable) but I am not proficient enough in SQL to understand how to get it to work using one query only (if it is even possible).
Thanks!

Answer 1

You should avoid doing queries with [not] in (select ...)
SELECT DISTINCT ObjectName
FROM Objects
INNER JOIN ObjectsDetails ON Objects.id = ObjectDetails.ObjectID
LEFT JOIN ExclusionTable on ExclusionTable.ComponentId = ObjectsDetails.ComponentID
where ExclusionTable.ComponentId is null;
This will retrieve only rows for which the ComponentID is not in ExclusionTable.
Update:
SELECT ObjectName
FROM Objects
INNER JOIN ObjectsDetails ON Objects.id = ObjectDetails.ObjectID
LEFT JOIN ExclusionTable on ExclusionTable.ComponentId = ObjectsDetails.ComponentID
group by ObjectName
having count(distinct ObjectsDetails.ComponentID) = sum(case when ExclusionTable.id is null then 1 else 0 end)
New approach, I think the only other way I could do it is basically to compare the number of components per object with the number of components in the object not included on the list. When these number are equal, no component is on the excluded list and we can show the object.
I'm sorry I can't make a test right now, please use EXPLAIN select ... to compare the queries, if they work.

Answer 2

Basically, if you need to get all objects not made from A or B, you need to get all objects EXCEPT those made from A or B.
SELECT DISTINCT Id, ObjectName
FROM Objects
WHERE Id NOT IN (
SELECT DISTINCT ObjectDetails.ObjectID
FROM ObjectDetails
INNER JOIN Components ON ObjectDetails.ComponentID = Components.Id
WHERE Components.ComponentName = 'A' OR Components.ComponentName = 'B'
)
Would that be what you're looking for?
EDIT: Of course, you can omit the join if you already have the component ids - then just put those in the where clause to filter them out.

Answer 3

select id, objectname
from Objects
left outer join
( select objectid from ObjectsDetails od inner join Exclusiontable et
on od.ComponentID= et.ComponentID) excludedid
on Objects.ID = excludedid.ObjectID and excludedid.ObjectID is null