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https://issues.apache.org/jira/browse/FLINK-22586?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Shuo Cheng updated FLINK-22586:
-------------------------------
Description:
Currently the precision and scale derivation is not properly for decimal data
arithmetics, e.g,
considering the following example:
{code:java}
select cast('10.1' as decimal(38, 19)) * cast('10.2' as decimal(38, 19)) from
T{code}
the result is `null`, which may confuses use a lot, because the result is
actually not that big.
The root cause is the precision derivation for the above multiplication is:
(38, 19) * (38, 19) -> (38, 38)
So there is no space for integral digits, which leads to null results.
was:
Currently the precision and scale derivation is not properly for decimal data
arithmetics, e.g,
considering the following example:
{code:java}
select cast('10.1' as decimal(38, 19)) * cast('10.2' as decimal(38, 19)) from
T{code}
the result is `null`, which may confuses use a lot, because the result is far
from overflow actually.
The root cause is the precision derivation for the above multiplication is:
(38, 19) * (38, 19) -> (38, 38)
So there is no space for integral digits, which leads to null results.
> Improve precision derivation for decimal arithmetics
> ----------------------------------------------------
>
> Key: FLINK-22586
> URL: https://issues.apache.org/jira/browse/FLINK-22586
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / Runtime
> Affects Versions: 1.13.0
> Reporter: Shuo Cheng
> Priority: Major
> Fix For: 1.14.0
>
>
> Currently the precision and scale derivation is not properly for decimal data
> arithmetics, e.g,
> considering the following example:
> {code:java}
> select cast('10.1' as decimal(38, 19)) * cast('10.2' as decimal(38, 19)) from
> T{code}
> the result is `null`, which may confuses use a lot, because the result is
> actually not that big.
> The root cause is the precision derivation for the above multiplication is:
> (38, 19) * (38, 19) -> (38, 38)
> So there is no space for integral digits, which leads to null results.
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