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https://issues.apache.org/jira/browse/FLINK-21125?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17271238#comment-17271238
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Sebastian Liu commented on FLINK-21125:
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Hi [~jark], [~lirui], what do you think about for this issue?
> Sum or Sum0 overflow quietly
> ----------------------------
>
> Key: FLINK-21125
> URL: https://issues.apache.org/jira/browse/FLINK-21125
> Project: Flink
> Issue Type: Bug
> Components: Table SQL / Planner
> Reporter: Sebastian Liu
> Priority: Major
>
> Overflow is not calculated correctly in the build-in sum function of Blink
> planner.
> For a aggregate calculation such as:
> {code:java}
> CREATE TABLE TestTable (
> amount INT
> );
> insert into TestTable (2147483647);
> insert into TestTable (1);
> SELECT sum(id) FROM TestTable;
> The result will be: -2147483648, which is an overflowed value and no
> exception was thrown. {code}
> The overflow occurs quietly and is difficult to detect.
> Compare the processing semantics of other systems：
> * *mysql*: provide two SQL mode for handling overflow. If strict SQL mode is
> enabled, MySQL rejects the out-of-range value with an error, and the insert
> fails, in accordance with the SQL standard. If no restrictive modes are
> enabled, MySQL clips the value to the appropriate endpoint of the column data
> type range and stores the resulting value instead. FYI:
> [https://dev.mysql.com/doc/refman/8.0/en/out-of-range-and-overflow.html]
> * *presto*: all numeric types are automatically auto Cast to Long type, and
> If the long is out of range, an exception is thrown to prompt user.
> IMO, exception hint is necessary, instead of quietly overflow.
>
>
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