[
https://issues.apache.org/jira/browse/FLINK-9559?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16590380#comment-16590380
]
ASF GitHub Bot commented on FLINK-9559:
---------------------------------------
hequn8128 commented on issue #6519: [FLINK-9559] [table] The type of a union of
CHAR columns of different lengths should be VARCHAR
URL: https://github.com/apache/flink/pull/6519#issuecomment-415459642
@pnowojski Hi, thanks for your review.
Yes, support VARCHAR(N) can solve the problem. As a workaround, we can cast
the literals to varchar to solve the problem, like: `case 1 when 1 then
cast('a' as varchar) when 2 then cast('bcd' as varchar) end`.
The behavior in strict SQL standard mode(SQL:2003) returns a CHAR(N) type
with blank-padded.
However, I test Oracle/SqlServer/Mysql and they all return the value without
blank-padded. Also, it seems that there is no way to turn blank-padded on.
This change will break implementations in Flink. Do you think we should make
it configurable?
Thanks, Hequn
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
> The type of a union of CHAR columns of different lengths should be VARCHAR
> --------------------------------------------------------------------------
>
> Key: FLINK-9559
> URL: https://issues.apache.org/jira/browse/FLINK-9559
> Project: Flink
> Issue Type: Bug
> Components: Table API & SQL
> Reporter: Hequn Cheng
> Assignee: Hequn Cheng
> Priority: Major
> Labels: pull-request-available
>
> Currently, If the case-when expression has two branches which return string
> literal, redundant white spaces will be appended to the short string literal.
> For example, for the sql: case 1 when 1 then 'a' when 2 then 'bcd' end, the
> return value will be 'a ' of CHAR(3) instead of 'a'.
> Although, this follows the behavior in strict SQL standard mode(SQL:2003). We
> should get the pragmatic return type in a real scenario without blank-padded.
> Happily, this problem has been fixed by
> [CALCITE-2321|https://issues.apache.org/jira/browse/CALCITE-2321], we can
> upgrade calcite to the next release(1.17.0) and override
> {{RelDataTypeSystem}} in flink to configure the return type, i.e., making
> {{shouldConvertRaggedUnionTypesToVarying()}} return true.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
