Capture part of URI and do not redirect.

Thank you all for your help.
I write this irule and solve my problem. 

when HTTP_REQUEST {
if { [HTTP::host] contains "example.com" }{
elseif { [HTTP::uri] starts_with "/abc" and not ([HTTP::uri] contains "abc-def") } {
HTTP::redirect /xyz

This is what happening.

example.com/abc -> redirecting to example.com/xyz
example.com/abc?=un -> redirecting to example.com/xyz

example.com/abc-def -> It stays as it is. This is my requirement.
example.com/abc-def?=un ->  It stays as it is. This is okay for me now. 

I was looking if there is anyway example.com/abc-def?=un can also be redirected to example.com/abc-def by modifying the irule above.