Select distinct a.WSTOCKTYPEID,a.wstockid,a.FREORDERQTY ,a.SStockcode,a.FREORDERQTYTRIG,a.FMINIMUMQTY,a.FQtyOnHand,coalesce(unit.FUNITQTY,1) FUNITQTY
,b.IMP_EXTID from stock a left join unit on 
unit.wunitid = a.wunitid join imp_link b on a.WStockid = b.WStockid and b.IMP_Sourceid =  
<@SOURCEID@>