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https://issues.apache.org/jira/browse/PIG-3269?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Cheolsoo Park updated PIG-3269:
-------------------------------
Description:
This is another language improvement using the same approach as in PIG-3268.
Currently, Pig has no support for IN operator. To mimic it, users often have to
concatenate several OR operators.
For example,
{code}
a = LOAD '1.txt' USING PigStorage(',') AS (i:int);
b = FILTER a BY
(i == 1) OR
(i == 22) OR
(i == 333) OR
(i == 4444) OR
(i == 55555);
{code}
But this can be re-rewritten in a more compact manner using IN operator as
follows:
{code}
a = LOAD '1.txt' USING PigStorage(',') AS (i:int);
b = FILTER a BY i IN (1,22,333,4444,55555);
{code}
I propose that we implement IN operator in the following manner:
* Add built-in UDFs that take expressions as args. Take for example the
aforementioned IN operator, we can define a UDF such as {{builtInUdf(i, 1, 22,
333, 4444, 55555)}}.
* Add syntactical sugar for these built-in UDFs.
was:
This is another language improvement using the same approach as in PIG-3268.
Currently, Pig has no support for IN operator. To mimic it, users often have to
concatenate several OR operators.
For example,
{code}
a = LOAD '1.txt' USING PigStorage(',') AS (i:int);
b = FILTER a BY
(i == 1) OR
(i == 22) OR
(i == 333) OR
(i == 4444) OR
(i == 55555);
{code}
But this can be re-rewritten in a more compact manner using IN operator as
follows:
{code}
a = LOAD '1.txt' USING PigStorage(',') AS (i:int);
b = FILTER a BY i IN (1,22,333,4444,55555);
{code}
I propose that we implement IN operator in the following manner:
* Add built-in UDFs that take expressions as args. Take for example the
aforementioned IN operator, we can define a UDF such as {{builtInUdf(i, 1, 22,
333, 4444, 55555)}}.
* Add syntactical sugar for these built-in UDFs.
Similarly to PIG-3268, this approach requires a limit on the number of values.
This is again because we need to populate the full list of possible args
schemas in {{EvalFunc.getArgToFuncMapping}}. For now, I arbitrarily chose 50,
but it can be easily changed.
ReviewBoard request: https://reviews.apache.org/r/10337/
> In operator support
> -------------------
>
> Key: PIG-3269
> URL: https://issues.apache.org/jira/browse/PIG-3269
> Project: Pig
> Issue Type: New Feature
> Components: internal-udfs, parser
> Affects Versions: 0.11
> Reporter: Cheolsoo Park
> Assignee: Cheolsoo Park
> Fix For: 0.12
>
> Attachments: PIG-3269-2.patch, PIG-3269-3.patch, PIG-3269.patch
>
>
> This is another language improvement using the same approach as in PIG-3268.
> Currently, Pig has no support for IN operator. To mimic it, users often have
> to concatenate several OR operators.
> For example,
> {code}
> a = LOAD '1.txt' USING PigStorage(',') AS (i:int);
> b = FILTER a BY
> (i == 1) OR
> (i == 22) OR
> (i == 333) OR
> (i == 4444) OR
> (i == 55555);
> {code}
> But this can be re-rewritten in a more compact manner using IN operator as
> follows:
> {code}
> a = LOAD '1.txt' USING PigStorage(',') AS (i:int);
> b = FILTER a BY i IN (1,22,333,4444,55555);
> {code}
> I propose that we implement IN operator in the following manner:
> * Add built-in UDFs that take expressions as args. Take for example the
> aforementioned IN operator, we can define a UDF such as {{builtInUdf(i, 1,
> 22, 333, 4444, 55555)}}.
> * Add syntactical sugar for these built-in UDFs.
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