一道数据库的笔试题目

有两个表

表一 AAA
种类mc     库存总量s1
A     997
B     1234

表二       BBB
种类mc     出库数量s1
A     105
A     213
B     116
B     211
B     303
用一条SQL语句求出A,B各剩下多少?

select distinct AA.T kind ,AA.S-(select sum(BB.S) sumnum from BB group by T having AA.T=BB.T) stock from AA,BB where AA.T=BB.T

结果：
kind stock
A     679
B     604

select distinct aa.king zhonglei,aa.zl-czl.sum kucun from aa,bb,(select king,sum(czl) sum from bb group by king) czl where aa.king=bb.king and aa.king=czl.king;
结果：
zhonglei kucun
a           679
b           604

select distinct aaa.mc zhonglei,aaa.sl-kczl.kcsl kucun from aaa,(select mc,sum(sl) kcsl from bbb group by mc) kczl where aaa.mc=kczl.mc;