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From "Xuefu Zhang (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-7373) Hive should not remove trailing zeros for decimal numbers
Date Tue, 22 Jul 2014 16:32:38 GMT

    [ https://issues.apache.org/jira/browse/HIVE-7373?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14070467#comment-14070467
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Xuefu Zhang commented on HIVE-7373:
-----------------------------------

For the same reason as we don't trim trailing zeros, personally I don't think we should append
zeros either. Some databases may choose to do so in formatting the output, to me this seems
questionable, non-essential at least.

This JIRA is to deal with trailing zero cases.

> Hive should not remove trailing zeros for decimal numbers
> ---------------------------------------------------------
>
>                 Key: HIVE-7373
>                 URL: https://issues.apache.org/jira/browse/HIVE-7373
>             Project: Hive
>          Issue Type: Bug
>          Components: Types
>    Affects Versions: 0.13.0, 0.13.1
>            Reporter: Xuefu Zhang
>            Assignee: Xuefu Zhang
>
> Currently Hive blindly removes trailing zeros of a decimal input number as sort of standardization.
This is questionable in theory and problematic in practice.
> 1. In decimal context,  number 3.140000 has a different semantic meaning from number
3.14. Removing trailing zeroes makes the meaning lost.
> 2. In a extreme case, 0.0 has (p, s) as (1, 1). Hive removes trailing zeros, and then
the number becomes 0, which has (p, s) of (1, 0). Thus, for a decimal column of (1,1), input
such as 0.0, 0.00, and so on becomes NULL because the column doesn't allow a decimal number
with integer part.
> Therefore, I propose Hive preserve the trailing zeroes (up to what the scale allows).
With this, in above example, 0.0, 0.00, and 0.0000 will be represented as 0.0 (precision=1,
scale=1) internally.



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