mysql java jdbc 如何 update select

public static void GetWeiLiaoMsg(String day) {
        try {
            conn = MysqlJdbc_sys_master.getConnection();
            String sql = "select a.city,a.n1,b.n2,c.n3 from (select city,sum(msg_count)as n1 from weiliao_msg WHERE push_time like '"+day+"%' group by city )a left join(select city,count(passenger_phone)as n2 from weiliao_yuyue WHERE push_time like '"+day+"%' group by city )b on a.city = b.city left join (select city,count(phone)as n3 from weiliao_phone WHERE push_time like '"+day+"%' group by city)c on a.city = c.city";
            stmt = conn.prepareStatement(sql);
            rs = stmt.executeQuery();
            conn.setAutoCommit(false);
            String sql_update = "update danke_FpResult set msg = ?,liudian=?,yuyue=? where city = ? and tag = 'allpush' and day = '"+day.replace("-", "")+"'";
            stmt = conn.prepareStatement(sql_update);
            while(rs.next()){
                stmt.setInt(1, rs.getInt(2));
                stmt.setInt(2, rs.getInt(3));
                stmt.setInt(3, rs.getInt(4));
                stmt.setString(4, rs.getString(1));
                stmt.addBatch();
            }
            stmt.executeBatch();
            conn.commit();
            System.out.println(new Date()+" insert into danke_FpResult all msg over!!");
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                stmt.close();
                conn.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }