Basically this:
SELECT SCandidateID
FROM dbo.CandidateSkills
WHERE Skill IN (@ssrs_skill_param)
GROUP BY SCandidateID
HAVING COUNT(*) = <number_of_values_in_skill_param>
But not sure how in SSRS to get a count of the values passed in. I can't remember if SSRS gives you a variable/property that equates to count or not.
Worst case, I would think you'd be able to do something like below, getting the total from the Skills "master" table:
HAVING COUNT(*) = (SELECT COUNT(*) FROM dbo.Skills WHERE Skill IN (@ssrs_skill_param))
Of course you can't use the CandidateSkills for that part, because it's possible a skill would be entered that no Candidate had, and you don't want it to drop out of the total.
SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.