Mysql（5.5）精度问题，带有十进制字段的函数SUM

Question

mysql数字列表的简单精度问题不能计算与单个计算相同的和。 （如何处理这个事件？）有一（1）分的差异？

行样本：

Select qty, (qty*21.25)
6.5  | 138.125
0.5  | 10.625
0.5  | 10.625
0.25 | 5.3125
1    | 21.25
2    | 42.5
1    | 21.25
2    | 42.5
2.5  | 53.125
2.5  | 53.125
2    | 42.5
3    | 63.75
3    | 63.75
3.5  | 74.375

样本2：

Select sum(qty), sum(amount)
30.25 | 642.8175

样本3：

Select 30.25*21.25
642.8125

Since the answer was so vague. Let try this. Can anyone explain why the mysql statement produces the wrong results. SELECT 6.875+3.125 10.00 Shouldn't this be 10.01

Answer 1

阅读此article。浮点数不会存储为精确值，因此可能存在计算精度问题