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https://issues.apache.org/jira/browse/HIVE-5848?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jason Dere resolved HIVE-5848.
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Resolution: Duplicate
Looks like this was resolved by HIVE-13380
> Hive's type promotion isn't correct
> -----------------------------------
>
> Key: HIVE-5848
> URL: https://issues.apache.org/jira/browse/HIVE-5848
> Project: Hive
> Issue Type: Improvement
> Affects Versions: 0.10.0, 0.11.0, 0.12.0
> Reporter: Xuefu Zhang
> Assignee: Xuefu Zhang
> Priority: Major
>
> When dealing with union all, arithmetic operators, and other places when type
> promotion is needed or a common type is determined, Hive would promote
> non-exact data types (float and double) to HiveDecimal. However, HIveDecimal
> is an exact type. Promoting a non-exact type to an exact type makes a false
> impression to the user that the data is exact. For instance, expression 3.14
> + 3.14BD produces an HiveDecimal number 6.28. However, the two are not
> equivalent, as the left operand is not exact. MySQL in this case produces a
> double 6.28, which is more reasonable.
> The problem was discovered in HIVE-3976. HIVE-5356 solves the problem for
> arithmetic operators, but there are more places where the problem exists. For
> instance, HIVE-5825 manifested the same issue.
> The purpose of this JIRA is to revisit the type casting and type promotion to
> make HIVE's behavior more in line with standard or other major database
> implementations.
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