File: Data.xml
1111
name 1
2222
name 2
8888
name 3
File: Query.xquery
declare function local:prod2ndDigit($prod as element()?) as xs:string? {
substring($prod/id, 2, 1)
};
doc("Data.xml")//car[local:prod2ndDigit(.) > '5']
Output:
8888
name 3