create or replace view monatl_forderung_heute as select m.id as mieter, w.id as wohnung, o.id as objekt, w.flaeche as flaeche, b.betrag as bkv_qm, (b.betrag * w.flaeche) as bkv, mz.betrag as miete_qm, (mz.betrag * w.flaeche) as miete from mieter m, objekt o, wohnung w, betriebskosten_vorauszahlung b, miete mz where o.id = w.objekt and w.id = m.wohnung and o.id = b.objekt and w.id = mz.wohnung and b.gueltig_ab <= now() and (b.gueltig_bis is null or b.gueltig_bis >= now()) and mz.gueltig_ab <= now() and (mz.gueltig_bis is null or mz.gueltig_bis >= now());