Firstly write the query you need to display:
Sqlcommand cmd;
sqlDataAdpater adap;
Dataset ds=new Dataset();
cmd=new SqlCommand("Select feidname from tablename,con);
adap = new SqlDataAdapter();
adap.Fill(ds,"table");
Crystalreport1 cr=new crystalReport();
cr.SetDataSource(ds.Tables[0]);
CrystalReportViewer1.ReportSource=cr;