如何转换为3小数点

Question

我创建了这个查询以查找行驶里程的AVG，但是我很难将数据格式化为3个小数点。

49.614112472330234

SELECT AVG(Mileage_Used)/SUM(time_to_sec(timediff(Lesson_Finish_Time,Lesson_Time))/3600) as Mileage_per_hour from LESSONS;

Answer 1

将值转换为具有正确精度的十进制类型：

select cast(<yourvalue> as decimal(10,3))

在你的情况下：

SELECT cast(AVG(Mileage_Used)/SUM(time_to_sec(timediff(Lesson_Finish_Time,Lesson_Time))/3600) as decimal(10,3)) as Mileage_per_hour 
from LESSONS