Filter with more than one criteria

Hi,

I have this bug wherein the onhand qty shows up wrongly in the inquiry form.Code is already there which joins the PriceDiscTable(which is used to display values in he inquiry form) with the InventSum,based on item id.What I have to do is,I have to check out the site,location,warehouse and serial no and filter it accordinglu.Has anyone done something of this sort?

Thanks,

G3