【急】BOM用量计算(100分)

Question

所用数据库：SQL2005
表tb_BOM_Relation
parent   child      qty
A        B          2
A        C          1
B        D          3
B        E          5
C        F          6
F        G          4
F        H          7
 
如何通过查询得到下面所示
leave   product   qty   totalqty
1       |-A        1    1
2        |-B       2    2
3         |-D      3    6 
3         |-E      5    10
2        |-C       1    1
3         |-F      6    6
4          |-G     4    24
4          |-H     7    42SQL

Answer 1

参考一下：http://www.cnblogs.com/sweting/archive/2009/06/08/1498483.html

Answer 2

http://blog.csdn.net/zjcxc/article/details/384939