Alexander,

A> in case any of the fields is "null" nothing is selected even when I pass
A> null value to its parameter.

A> I understand that this is how things are meant to be, but can you
A> suggest something to overcome this issue

old story, read the archives.
No simple solution that I know of, though.

P.S. Please start a new thread for new posts. Hitting Reply and
clearing the subject and body areas is not enough.

Ciao
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Nando mailto:nandod@...