SELECT sl.sms_prefix,sum( sl.parts ),cp.country_name,CAST(SUM(sl.parts) AS NUMERIC(10,4)) * CAST(cp.price AS NUMERIC(10,4))
FROM sms_log sl,sms_transaction st,country_prefix cp
WHERE st.customer_id =1
AND st.sendtime >=1329865200
AND st.sendtime <=1330037999
AND st.sms_trans_id = sl.trans_id
AND sl.sms_prefix = cp.prefix
AND st.customer_id = cp.customer_id
GROUP BY sl.sms_prefix
LIMIT 0,30

结果：

sms_prefix  sum( sl.parts )     country_name    price   total
==================================================================================
45            2                        Denmark   0.01   0.019999999552965
63            3                        Philippines   2  6

正如你所看到的,丹麦的“总”不正确,因为sum(sl.parts)= 2乘以0.01,总数应该是0.02.

价格领域是FLOAT我怎么可以CAST总共浮动？

问候,