Cross Join! In SQL Server, but I really only need about a third of the rows?

Question

Ok, so I'm not sure if I'm going about this the right way. But my scenario is I've got a stored procedure I'd like to test using all the possible combinations of the inputs it takes.

Let's say I have a stored procedure that takes two parameters, like this:

set UsefulValue = exec spMyStoredProc @ProfileID, @RoleID

Now in my case, ProfileID means something like people and RoleID means something like system roles. I'm being a little general here on purpose. The point is, I have about 60,000 defined people, and about 600 defined roles.

Unfortunately, the system I'm testing is COMPLICATED, like bad-hair-day complicated, and I really need to run this procedure through its paces.

Ok, with me so far? Hopefully you are; check out this sql to generate the data that I will eventually pass to the stored procedure:

    select profiles.ProfileID, roles.RoleID from Profile profiles
cross join dbo.DefinedRoles roles

This is actually pretty good, but the problem is it's taking forever to run, and frankly I don't need every permutation of these two values.

So I tried constricting the result set like so:

select top 300000 profiles.ProfileObjID, roles.RoleName from dbo.Profile profiles
cross join dbo.rj_v_DefinedRoles roles 

But oops! That constricts the final result, so I end up with only a result that is pretty much 2-3 roles (depending on what I pass to the top verb) and with a ProfileID for each person.

What I'd like to have, my goal, is to get results for all the roles I have (about 600) and for each one, maybe only use half of the ProfileIDs instead of the whole shebang.

So does that make sense what I'm asking?

Answer 1

This worked well. GREATLY cuts down on the time it takes to execute the cross join.

select profiles.ProfileObjID, roles.RoleName
from dbo.rj_v_DefinedRoles roles
cross join dbo.Profile profiles
where ProfileObjId in (select ProfileObjId from dbo.Profile
                    where ProfileObjId between 10000 and 11000) 

Answer 2

If I understand the problem you want a number of test cases, but do not want them generated in favour of a specific role / person (which cross join is doing to you).

select top 300000
profiles.ProfileObjID, roles.RoleName 
from dbo.Profile profiles 
cross join dbo.rj_v_DefinedRoles roles
order by newid()

The order by will randomise your results, then top the results to get a random test set of data. This will not of course guarentee any specific role / person is in the final results, it's a percentage chance etc.

Answer 3

You could use ROW_NUMBER() in a couple of different places to select a portion of your data...

-- Maximum of 20,000 rows per RoleID
WITH
  combinations AS
(
  SELECT
    roles.RoleID,
    profiles.ProfileID,
    ROW_NUMBER() OVER (PARTITION BY roles.RoleID) AS profile_sequence_id
  FROM
    Profile          profiles
  CROSS JOIN
    dbo.DefinedRoles roles
)
SELECT
  *
FROM
  combinations
WHERE
  profile_sequence_id < 20000

Or...

-- Maximum of 20,000 rows per RoleID
WITH
  profiles AS
(
  SELECT
    *,
    ROW_NUMBER() OVER (PARTITION BY 1) AS profile_sequence_id
  FROM
    Profile
)
SELECT
  roles.RoleID,
  profiles.ProfileID
FROM
  dbo.DefinedRoles roles
CROSS JOIN
  profiles
WHERE
  profiles .profile_sequence_id < 20000

Answer 4

Have you tried using the DISTINCT keyword?

select DISTINCT profiles.ProfileObjID, roles.RoleName from dbo.Profile profiles cross join dbo.rj_v_DefinedRoles roles