If there are say more than 100 subforums and the user selects all of them except a couple of them (in the Fluid View Filter Checkboxes widget) which s/he is not interested in viewing their topics, it would be more performant to count the number of forums and number of checked boxes:

If the number of checked boxes is greater than the number of unchecked boxes then

    WHERE forumId NOT IN (x,y,x)   // Just address the unchecked forumIds to minimize the number of IN clauses

//  as opposed to - WHERE forumId IN (97 subforums IDs)

else

    WHERE forumId IN (a,b,c,d,e,f...)

end if

 

HTH

 

That could be true from an SQL perspective but... it's probably more performant to ask yourself why any community needs 100 subforums. Think about usability from a human perspective.