请帮写一个SQL查询,100大分，赶紧来抢啊(100分)

现有下一表：
SERIAL_NO DEPART NUM PRICE TYPE
1 1 3 10.10 1
2 2 10 9.00 1
3 5 3 8.90 2
4 3 5 4.30 1
5 7 10 1.90 2
... ... ... ... ...
部门（DEPART）有多个，类型（TYPE）有多种，请统计出类型为1 和2
的NUM*PRICE (类型1 SUM_IN, 类型2 SUM_OUT)，查询出后列出的表为：
DEPART SUM_IN SUM_OUT
1 .... ....
2 .... ....
3 .... ...
...

select a.depart as depart, sum(a.num*a.price) as sum_in, sum(b.num*b.price) as sum_out
from your_table a, your_table b
where a.depart = b.depart and a.type = 1 and b.type = 2
group by depart order by depart

SELECT DEPART,SUM(NUM*PRICE*(2-TYPE)) AS SUM_IN,
SUM(NUM*PRICE*(TYPE-1)) AS SUM_OUT
FROM TABLE
GROUP BY DEPART
ORDER BY DEPART

Another_eYes:
与本人写法相同，统计结果不太正确