Modules & VBA :: How To Implement Variable In Nested Query

I have made this sql statement in VBA where rubriek = a variable but I dont know how to implement a variable in a nested query.

SELECT "rubriek, SUM(verkoopprijs) as prijzen
FROM voorwerp
(inner join VoorwerpInRubriek on voorwerp.voorwerpnummer = VoorwerpInRubriek.voorwerp)
inner join Rubriek on rubriek.rubrieknummer = VoorwerpInRubriek.rubriekOpLaagsteNiveau
where rubriek in (select rubrieknummer
from rubriek
where rubriek = variable name
)
group by rubriek"

Do I have to treat it as a normal select query or is there something speical that I have to do ?