MySQL - 我如何总是四舍五入小数？
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MySQL - How can I always round up decimals?
提问by quidpro
For instance I have the following value:
例如，我有以下价值：
0.000018
0.000018
This is 6 decimal places, but I want to round it up the nearest whole 4th decimal place, so that:
这是小数点后 6 位，但我想将其四舍五入到最接近的第 4 位小数，以便：
0.000018 -> 0.0001
0.000018 -> 0.0001
I've played with the round() funcction but if I simply use the round function:
我玩过 round() 函数，但如果我只是使用 round 函数：
round(0.000018,4) = 0.0000
round(0.000018,4) = 0.0000
When dealing with decimals for financial purposes, in this case one needs to round up and charge the customer instead of giving them a freebie! But round()will go round up or down depending on value, I need to consistently round up.
当出于财务目的处理小数时，在这种情况下，需要四舍五入并向客户收费，而不是给他们免费赠品！但是round()会根据价值向上或向下取整，我需要始终向上取整。
Is there a simple way of doing this?
有没有一种简单的方法可以做到这一点？
回答by Nanne
You can use ceil (ceiling). It only rounds up, so you'll have to multiply with 10000, do the ceil and then divide the result again.
您可以使用ceil (天花板)。它只会四舍五入，因此您必须乘以 10000，计算 ceil，然后再次除以结果。
So ceil(0.000145* 10000) = ceil(1.45) = 2Divide back and you'll have 0.0002
所以ceil(0.000145* 10000) = ceil(1.45) = 2划分回来，你就会有0.0002
EDIT: wait, wut? that doesn't work. I mean FLOORobviously but the working is the same :D
The manual is on the same page too :)
编辑：等等，哇？那行不通。我的意思FLOOR很明显，但工作是一样的:D 手册也在同一页上:)
So floor(0.000145* 10000) = floor(1.45) = 1Divide back and you'll have 0.0001
所以floor(0.000145* 10000) = floor(1.45) = 1划分回来，你就会有0.0001
回答by Hyman Nord
There's another method, which is to add half a multiple of 10. For example: round(x+0.005, 2)where x is 0.923 = 0.93 which reduces the maximum floating point division error.
还有另一种方法，就是将 10 的倍数相加。例如：round(x+0.005, 2)其中 x 是 0.923 = 0.93，这样可以减少最大浮点除法误差。
回答by Saket
Use ROUND(X,D), which rounds the value X to D decimal places.
使用ROUND(X,D)，将值 X 舍入到 D 小数位。
