Martin’s idea of using group by is a good idea. You could as well get replace "for $servNos in" by "let $servNos :=", because you can compare multiple values in a predicate.

I am wondering, however, if your query isn’t doing the same thing multiple times. I guess the following query is equivalent?

collection("752150_Voice_OCTOBER-18_Billed")/SUBCUSTBRK [AccNo/@NO = "9800964"] [DOB >='2018-10-01' and DOB <='2018-10-31'] [ServInfo != '0']

Dear basex,

Please find attachment for sample xml,Like sample xml we are added multiple xml's to the collection .Below query is my XQuery ,It is taking huge time,Can we optimize this query.

My collection size is nearly 1.5 GB

let $entriesDisplay := 'Display All' let $Rows := (collection("752150_Voice_OCTOBER-18_Billed")/SUBCUSTBRK[AccNo[@NO = (9800964)]][DOB >='2018-10-01' and DOB <='2018-10-31'][ServInfo!=0])

let $accNo := "9800964" let $accWiseTags := $Rows[AccNo[@NO = $accNo]] for $servNos in distinct-values($accWiseTags/CONN/@NO) let $eachRow := $accWiseTags[CONN[@NO=$servNos]]

return $eachRow

Have you tried to use `group-by` e.g.

for $r in $accWiseTags

group by $no := $r/CONN/@NO

return $r

?