how to retreive specific data from database in c# winsform

SqlConnection con = new SqlConnection();

con.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\odt\Documents\Loanapp.mdf;Integrated Security=True;Connect Timeout=30";

con.Open();

SqlCommand cmd = new SqlCommand();

cmd.Connection = con;

cmd.CommandText = "select * FROM loanapproval where loanapprove=@empno";