Select query not working

Hi,

Im using this select query in my RFC:

select <field list> from but000 into table IT_but000 where type = '2' and partner in r_client.

Where r_client is a range having values for diffrent partners. Issue is when there is no value in r_client query is not returning any record. ideally it should return records based on condition "type = 2". can anybody help me in this.

Rgds

Sudhanshu