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https://issues.apache.org/jira/browse/HIVE-11741?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Thejas M Nair updated HIVE-11741:
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Assignee: Guilherme Braccialli (was: Thejas M Nair)
> Add a new hook to run before query parse/compile
> ------------------------------------------------
>
> Key: HIVE-11741
> URL: https://issues.apache.org/jira/browse/HIVE-11741
> Project: Hive
> Issue Type: New Feature
> Components: hpl/sql, Parser, SQL
> Affects Versions: 1.2.1
> Reporter: Guilherme Braccialli
> Assignee: Guilherme Braccialli
> Priority: Minor
> Labels: patch
> Attachments: HIVE-11741.patch
>
>
> It would be nice to allow developers to extend hive query language, making
> possible to use custom wildcards on queries.
> People uses Python or R to iterate over vectors or lists and create SQL
> commands, this could be implemented directly on sql syntax.
> For example this python script:
> >>> sql = "SELECT state, "
> >>> for i in range(10):
> ... sql += " sum(case when type = " + str(i) + " then value end) as
> sum_of_" + str(i) + " ,"
> ...
> >>> sql += " count(1) as total FROM table"
> >>> print(sql)
> Could be written directly in extended sql like this:
> SELECT state,
> %for id = 1 to 10%
> sum(case when type = %id% then value end) as sum_of_%id%,
> %end%
> , count(1) as total
> FROM table
> GROUP BY state
> This kind of extensibility can be easily added if we add a new hook after
> VariableSubstitution call on Driver.compile method.
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