[
https://issues.apache.org/jira/browse/CALCITE-111?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17482104#comment-17482104
]
Julian Hyde commented on CALCITE-111:
-------------------------------------
I don't think the MySQL {{CONVERT}} function is based on the SQL standard. In
fact it's more similar to {{CAST}}. I think it should be out of scope for this
discussion. (We can discuss a new function - let's call it {{MYSQL_CONVERT}} -
in another thread, if you wish.)
[Postgres CONVERT|https://postgrespro.com/docs/postgresql/9.5/functions-string]
seems to comply with the standard; its {{TRANSLATE}} is based on Oracle's
{{TRANSLATE}}, which is unrelated (Calcite calls it {{TRANSLATE3}}).
In the standard, {{CONVERT}} and {{TRANSLATE}} are related (they both deal with
character sets) but are not identical:
* {{CONVERT}} has arguments {{(string bytea, src_encoding name, dest_encoding
name)}}, for example {{convert('text_in_utf8', 'UTF8', 'LATIN1')}}
* I haven't checked the spec but I think {{TRANSLATE}} has arguments {{(string
bytea, translation name)}}.
I have no strong opinion whether you assign one SqlKind or two. I think the
first step is to write a few use cases (SQL expressions and what the result
should be). Can you write those here? Then create a test based on those cases,
and get it to pass.
> Support CONVERT function, for changing character sets
> -----------------------------------------------------
>
> Key: CALCITE-111
> URL: https://issues.apache.org/jira/browse/CALCITE-111
> Project: Calcite
> Issue Type: Improvement
> Reporter: GitHub Import
> Assignee: ZheHu
> Priority: Major
> Labels: github-import
>
> Support the CONVERT function, to convert strings from one character set to
> another.
> CONVERT is defined in SQL:2011 as a feature called <character
> transliteration>. Here is an example:
> ```sql
> SELECT * FROM emp WHERE CONVERT(name USING UTF16) = u&'\82f1\56fd'
> ```
> The <a
> href="http://dev.mysql.com/doc/refman/5.0/en/charset-convert.html";>MySQL
> site</a> has other examples.
> ---------------- Imported from GitHub ----------------
> Url: https://github.com/julianhyde/optiq/issues/111
> Created by: [julianhyde|https://github.com/julianhyde]
> Labels: enhancement,
> Created at: Tue Jan 14 03:40:53 CET 2014
> State: open
--
This message was sent by Atlassian Jira
(v8.20.1#820001)
