This is covered in the Report Studio user guide (aka online help).
http://www.ibm.com/support/knowledgecenter/SSEP7J_10.2.2/com.ibm.swg.ba.cognos.ug_cr_rptstd.10.2.2.doc/t_cr_rptstd_wrkdat_filter_data_rel.html#cr_rptstd_wrkdat_filter_data_rel
http://www.ibm.com/support/knowledgecenter/SSEP7J_10.2.2/com.ibm.swg.ba.cognos.ug_cr_rptstd.10.2.2.doc/t_cr_rptstd_wrkdat_filter_data_rel.html#cr_rptstd_wrkdat_filter_data_rel