插入数据库时​​，php round无法正常工作

Question

I have a problem with round and inserting into database. Doing the following and trying to insert $y into Mongo will insert it with multiple decimals (similar to what you see from var_export below).

How can I fix this, as I need to have exactly 2 decimals.

<?php

$y = round(348.78 + 348.78 * 19/100, 2 );

var_dump($y);
var_export ($y);

This is only to display the difference on how it gets inserted into Mongo.

float(415.05)
415.05000000000001

Answer 1

Float datatype is not a good option to represent high precision numbers. Decimal is made for that.

See here how (and why) to use decimal numbers with mongoDB