[jira] [Updated] (CALCITE-5771) Apply two different NULL semantics for CONCAT function(enabled in MySQL、Postgresql、BigQuery and MSSQL)

["ZheHu (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CALCITE-5771?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

ZheHu updated CALCITE-5771:
---------------------------
    Summary: Apply two different NULL semantics for CONCAT function(enabled in MySQL、Postgresql、BigQuery and MSSQL)  (was: Apply two different NULL semantics for CONCAT function(enabled in MySQL、Postgresql and BigQuery))

> Apply two different NULL semantics for CONCAT function(enabled in MySQL、Postgresql、BigQuery and MSSQL)
> ------------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-5771
>                 URL: https://issues.apache.org/jira/browse/CALCITE-5771
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 1.34.0
>            Reporter: ZheHu
>            Assignee: ZheHu
>            Priority: Major
>
> We now have one CONCAT_FUNCTION which is enabled in MySQL、Postgresql、BigQuery, it always returns NULL when any of the arguments is NULL, and it accepts at least 2 arguments.
> The following table describes how different database products define CONCAT function:
> || DB Product || Argument type in CONCAT || Argument num in CONCAT || Result ||
> |MySQL|string|at least 1|returns null if any argument is null, otherwise return string|
> |Postgresql|any(cast to string)|at least 1|always return string, null is treated as empty string|
> |BigQuery|string|at least 1|returns null if any argument is null, otherwise return string|
> For MySQL and BigQuery, we can reuse the current CONCAT_FUNCTION(but need to change the accepted argument number). We also need another CONCAT function for Postgresql that treats NULL as empty String.



--
This message was sent by Atlassian Jira
(v8.20.10#820010)