let $subbrk := (collection("DATABSE")/SUBCUSTBRK[AccNo[@NO = (12345)]][DOB >= '2019-10-01' and DOB <= '2019-10-31']) 
let $detailUsageTxn := $subbrk/DETAIL/TRANSACTION[@Usage = 'usage'] 
let $DistCallTypes := distinct-values($detailUsageTxn/SUB_SECTION/@Type) 
let $allmonths := distinct-values($subbrk/Month) 
let $rowcnt := count($detailUsageTxn/SUB_SECTION) 
let $months := $allmonths 
let $opttype := 'NumVal' 
let $durop := 'hh:mm:ss'
 return   (  
  if($DistCallTypes!='')then (
    
    for $month in $months  
     return     <R>      
       <GRPBY>{ $month }</GRPBY>{            
              if($opttype = 'NumVal')
               then      
              for $ct in $DistCallTypes    
           let $ctCnt := sum($detailUsageTxn/SUB_SECTION[data(@Type) = data($ct) ]/@Calls)                
             return element { replace(concat('_',data($ct)),'(\.|\[|\]|\\|\||\-|\^|\$|\?|\*|\+|\{|\}|\(|\)| |&apos;)', '_') }
                {xs:decimal($ctCnt)}         
                  
                        
	}   </R>  

)

else()    
   
   )