我用COUNT 相除算出来的数字怎么都是1或者0
1-COUNT(D.upc)/COUNT(D.差值)
1-COUNT(D.upc)*1.00/COUNT(D.差值)
应该是你的COUNT(D.upc)和COUNT(D.差值)算出来相等了,所以相除为1,1-1等于0;
其次是COUNT(D.upc)为0,1-0等于1;