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https://issues.apache.org/jira/browse/CALCITE-7007?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17981839#comment-17981839
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Lorenzo Affetti commented on CALCITE-7007:
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[~julianhyde] thank you for your considerations!
What you say is that "*" is not for "all columns" in the aggregate context and
it makes sense.
What you explain above is that `count([col, ]*)` means "count where the values
at the columns specified are not null".
However, `count(*)` does not mean "count where all the values are not null" but
the exact opposite.
In the context of this issue, I think the start operator in general is well
known to be considered as "all columns".
Can we consider `count(*)` semantics as just an exception and preserve its
semantics when passing to functions?
I can find at least 1 example, in Postgres, in which this semantics is used:
[https://www.postgresql.org/docs/9.2/xfunc-sql.html] (at 35.4.3).
However, in standard SQL, `*` seem to just be used for `select {*}` and
`count({*})`.
> Support STAR operator in UDF calls
> ----------------------------------
>
> Key: CALCITE-7007
> URL: https://issues.apache.org/jira/browse/CALCITE-7007
> Project: Calcite
> Issue Type: Wish
> Reporter: Lorenzo Affetti
> Priority: Minor
>
> As one can perform aggregate operations by passing the `*` operator:
>
> {code:java}
> select count(*) from table where ...;{code}
>
> One might be able to use `*` in UDF calls, e.g.:
>
> {code:java}
> select myUDF(*) from table where ...;{code}
> With the meaning of "every column".
>
> So, say that `table` schema has 3 columns: `id`, `name`, `description`, this:
> {code:java}
> select myUDF(*) from table where ...;
> {code}
> Would be equivalent to this:
> {code:java}
> select myUDF(id, name, description) from table where ...; {code}
> This issue is related to Flink's
> https://issues.apache.org/jira/browse/FLINK-35466.
> Flink already support `*` for UDF calls in its Table API and uses Calcite for
> the SQL API.
> Support for this kind of SQL calls introduces a change in Calcite visitors.
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