BigQuery 中的 NUMERIC 和 FLOAT 有什么区别? [英] What is the difference between NUMERIC and FLOAT in BigQuery?

问题描述

我阅读了文档:

这不是错误 - 这正是

I read the docs: https://cloud.google.com/bigquery/docs/reference/standard-sql/data-types https://cloud.google.com/bigquery/pricing#data

I know that FLOAT is 8 bytes while NUMERIC is 16 bytes Is that the only difference? The docs says that NUMERIC can range -99999999999999999999999999999.999999999 to 99999999999999999999999999999.999999999 but it doesn't specify the range for FLOAT.

解决方案

I like the current answers. I want to add this as a proof of why NUMERIC is necessary:

SELECT 
  4.35 * 100 a_float
  , CAST(4.35 AS NUMERIC) * 100 a_numeric

This is not a bug - this is exactly how the IEEE defines floats should be handled. Meanwhile NUMERIC exhibits behavior closer to what humans expect.

For another proof of NUMERIC usefulness, this answer shows how NUMERIC can handle numbers too big for JavaScript to normally handle.

Before you blame BigQuery for this problem, you can check that most other programming languages will do the same. Python, for example:

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