I have coded session_id same as other functions that work without
parenthesis. That means, in Drill, there has to be a way to make a function
to work without parenthesis (through Calcite). I researched enough and I
could not find the place where I can configure to make it work so.... Drill
Gurus have to help me here...

Best Regards,
Nagu.

On Wed, Dec 21, 2016 at 1:20 AM, Jinfeng Ni <[email protected]> wrote:

> For function without parentheses, Calcite validator checks a
> SqlIdentifier against validator's operatorTable. If such identifier
> appears in the operatorTable, the SqlIdentifier is converted to a
> SqlCall. For your use case, you probably need add such function into
> operatorTable. You may follow Julian's suggestion of looking at
> CURRENT_DATE function.
>
> 1. https://github.com/apache/calcite/blob/master/core/src/main/
> java/org/apache/calcite/sql/SqlIdentifier.java#L302-L308
>
> On Tue, Dec 20, 2016 at 11:19 AM, Julian Hyde <[email protected]> wrote:
> > I don’t think you need to change the parser, just the validator (the
> changes to SqlOperator.getSyntax I described already). The parser will
> parse an identifier, and the validator will recognize that it is a call to
> a function with no arguments.
> >
> > Unless Drill has diverged further from Calcite than I imagine it has.
> >
> > Julian
> >
> >
> >> On Dec 20, 2016, at 10:51 AM, Sudheesh Katkam <[email protected]>
> wrote:
> >>
> >> I do not know the exact answer.
> >>
> >> Quite likely the Calcite parser needs to be changed, this blob:
> >>
> >> https://github.com/apache/calcite/blob/master/core/src/main/
> codegen/templates/Parser.jj#L4765 <https://github.com/apache/cal
> cite/blob/master/core/src/main/codegen/templates/Parser.jj#L4765>
> >>
> >> Drill extends the Calcite parser, not sure if the change can be made
> here:
> >>
> >> https://github.com/apache/drill/blob/master/exec/java-exec/
> src/main/codegen/includes/parserImpls.ftl <https://github.com/apache/dri
> ll/blob/master/exec/java-exec/src/main/codegen/includes/parserImpls.ftl>
> >>
> >> Thank you,
> >> Sudheesh
> >>
> >>> On Dec 19, 2016, at 3:00 PM, Nagarajan Chinnasamy <
> [email protected]> wrote:
> >>>
> >>> Hi Julian Hyde,
> >>>
> >>> Thanks for your response. I am looking for the Drill way of doing it.
> >>>
> >>> In fact I have coded session_id function exactly as one of other
> >>> ContextFunctions of Drill. I seem to be missing something :(
> >>>
> >>>
> >>>
> >>>
> >>> Best Regards,
> >>> Nagu.
> >>>
> >>> On Mon, Dec 19, 2016 at 1:30 PM, Nagarajan Chinnasamy <
> >>> [email protected]> wrote:
> >>>
> >>>> Hi,
> >>>>
> >>>> Am developing a UDF called SESSION_ID as detailed in issue:
> >>>>
> >>>>   https://issues.apache.org/jira/browse/DRILL-5043
> >>>>
> >>>> It does not take any input parameters. Now, I can only invoke it using
> >>>> parenthesis as in:
> >>>>
> >>>>   SELECT SESSION_ID() FROM (Values(1));
> >>>>
> >>>> I would like to know what do I need to do if I need to invoke it
> without
> >>>> paranthesis like:
> >>>>
> >>>>   SELECT SESSION_ID FROM (Values(1));
> >>>>
> >>>> Appreciate your input.
> >>>>
> >>>> Best Regards,
> >>>> Nagu.
> >>>>
> >>
> >
>

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