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From Paul Rogers <prog...@mapr.com>
Subject Re: Invoking UDF that doesn't have parameters without paranthesis [Resolved]
Date Sat, 14 Jan 2017 18:30:14 GMT
Congrats! Nice job!

- Paul

> On Jan 14, 2017, at 5:52 AM, Nagarajan Chinnasamy <nagarajanchinnasamy@gmail.com>
wrote:
> 
> Success :) I could invoke SESSION_ID without parenthesis. Following did the
> trick:
> 
> 1. In DrillSqlOperator, overriding getSyntax method to return
> SqlSyntax.FUNCTION_ID
> 2. In DrillOperatorTable, adding operator when SqlSyntax is (FUNCTION ||
> FUNCTION_ID)
> 
> Thanks for your inputs.
> 
> Best Regards,
> Nagu.
> 
> On Fri, Jan 13, 2017 at 1:30 AM, Nagarajan Chinnasamy <
> nagarajanchinnasamy@gmail.com> wrote:
> 
>> The  CURRENT_DATE is constructed using the SqlFunction constructor:
>> 
>>    public SqlFunction(String name,
>>        SqlKind kind,
>>        SqlReturnTypeInference returnTypeInference,
>>        SqlOperandTypeInference operandTypeInference,
>>        SqlOperandTypeChecker operandTypeChecker, SqlFunctionCategory
>> category)
>> 
>> Whereas the DrillSqlOperator (derived from SqlFunction) is using the
>> following constructor variation:
>> 
>>    super(new SqlIdentifier(name, SqlParserPos.ZERO),
>>        sqlReturnTypeInference,
>>        null,
>>        Checker.getChecker(argCountMin, argCountMax), //
>> SqlOperandTypeChecker
>>        null,
>>        SqlFunctionCategory.USER_DEFINED_FUNCTION);
>> 
>> In DrillSqlOperator (derived from SqlFunction), I  tried:
>> 
>>    1. setting OperandTypeChecker value to OperandTypes.NILADIC
>>    2. Overriding getSyntax method to return SqlSyntax.FUNCTION_ID
>> 
>> Both of the above did not help.
>> 
>> When invoked without parenthesis, I get the following exception:
>> 
>> 0: jdbc:drill:zk=local> select session_id from (values(1));
>> Jan 13, 2017 12:58:00 AM org.apache.calcite.sql.validate.SqlValidatorException
>> <init>
>> SEVERE: org.apache.calcite.sql.validate.SqlValidatorException: Column
>> 'session_id' not found in any table
>> Jan 13, 2017 12:58:00 AM org.apache.calcite.runtime.CalciteException
>> <init>
>> SEVERE: org.apache.calcite.runtime.CalciteContextException: From line 1,
>> column 8 to line 1, column 17: Column 'session_id' not found in any table
>> Error: VALIDATION ERROR: From line 1, column 8 to line 1, column 17:
>> Column 'session_id' not found in any table
>> 
>> Looking for your inputs to resolve this issue...
>> 
>> Best Regards,
>> Nagu.
>> 
>> On Wed, Dec 21, 2016 at 1:20 AM, Jinfeng Ni <jni@apache.org> 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 <jhyde@apache.org> 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 <skatkam@maprtech.com>
>>> 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 <
>>> nagarajanchinnasamy@gmail.com> 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 <
>>>>>> nagarajanchinnasamy@gmail.com> 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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