统计算法求解

模拟数据表
catid（目录ID）       upid（上级目录ID）                                 num（值全部为1）
1                                   0      （0无上层目录）                                1
2                                  0                                                                    1
3                                  0
4                                  1       （上层目录ID号为1）
5                                  1
6                                  2       （上层目录ID号为2）
7                                  4       （上层目录ID号为4）
8                                  7       （上层目录ID号为7）
9                                  5        （上层目录ID号为5）
意思就是计算出  每个目录下所有子目录的num总数  和每个子目录下的num总数   需要得到的结果  
catid   1        得到   6
catid   2       得到   2
            3                  1
            4                  2
            5                  2
            6                  1
            7                  2
            8                  1
            9                  1