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https://issues.apache.org/jira/browse/HIVE-24528?focusedWorklogId=552079&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-552079
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ASF GitHub Bot logged work on HIVE-24528:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 13/Feb/21 00:45
Start Date: 13/Feb/21 00:45
Worklog Time Spent: 10m
Work Description: github-actions[bot] commented on pull request #1771:
URL: https://github.com/apache/hive/pull/1771#issuecomment-778531491
This pull request has been automatically marked as stale because it has not
had recent activity. It will be closed if no further activity occurs.
Feel free to reach out on the [email protected] list if the patch is in
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Issue Time Tracking
-------------------
Worklog Id: (was: 552079)
Time Spent: 1h 10m (was: 1h)
> Wrong implicit type conversion when comparing decimals and strings
> ------------------------------------------------------------------
>
> Key: HIVE-24528
> URL: https://issues.apache.org/jira/browse/HIVE-24528
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2
> Affects Versions: 2.3.0
> Reporter: Stamatis Zampetakis
> Assignee: Stamatis Zampetakis
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> In many cases when comparing decimals and strings (literals/columns) the
> comparison is done using doubles which can create some quite unexpected
> results in the answers of queries.
> {code:sql}
> create table t_str (str_col string);
> insert into t_str values ('1208925742523269458163819');
> select * from t_str where str_col=1208925742523269479013976;
> {code}
> The SELECT query brings up one row while the filtering value is not the same
> with the one present in the string column of the table. The problem is that
> both types are converted to doubles and due to loss of precision the values
> are deemed equal.
> The same happens during the join of a decimal with a string type.
> {code:sql}
> create table t_dec (dec_col decimal(25,0));
> insert into t_dec values (1208925742523269479013976);
> select * from t_dec inner join t_str on dec_col=str_col;
> {code}
> The join result contains one row although the values are not equal.
> Implicit type conversions are working differently in every DBMS and for some
> of them (e.g., mysql) the above behavior is normal or not allowed at all
> (e.g. Postgres).
> In the past, Hive used to compare decimal with string columns by converting
> to decimals but this behavior changed in 2.3.0 (with HIVE-13380). It seems
> that this behavior change was not intentional since following jiras (e.g.,
> HIVE-18434) imply that comparison of decimals with strings should be done
> using decimals. Since decimal is an exact numeric it appears a more
> appropriate type for comparing decimals and strings.
> The goal of this issue is to change the implicit conversion of decimals with
> strings to doubles and use decimals instead.
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