[jira] [Work logged] (HIVE-25230) add position and occurrence to instr()

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-25230?focusedWorklogId=766984&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-766984 ]

ASF GitHub Bot logged work on HIVE-25230:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 06/May/22 01:35
            Start Date: 06/May/22 01:35
    Worklog Time Spent: 10m 
      Work Description: stiga-huang opened a new pull request, #2378:
URL: https://github.com/apache/hive/pull/2378

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   ### What changes were proposed in this pull request?
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   This PR extends the INSTR() function to support optional position and occurrence arguments, which is supported in Oracle, Impala, etc.
   https://docs.oracle.com/database/121/SQLRF/functions089.htm#SQLRF00651
   https://impala.apache.org/docs/build/html/topics/impala_string_functions.html#string_functions__instr
   
   ### Why are the changes needed?
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     1. If you propose a new API, clarify the use case for a new API.
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   This provides users more functionality in the INSTR() function.
   It also helps to reduce the SQL difference between Hive and Impala.
   
   ### Does this PR introduce _any_ user-facing change?
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   Yes, INSTR() will have two more optional arguments, which needs document as well.
   ```
   instr(str, substr[, pos[, occurrence]]) - Returns the index of the given occurrence of substr in str after position pos
   
   pos is a 1-based index. If pos < 0, the starting position is
   determined by counting backwards from the end of str and then Hive
   searches backward from the resulting position.
   occurrence is also a 1-based index. The value must be positive.
   If occurrence is greater than the number of matching occurrences,
   the function returns 0.
   If either of the optional arguments, pos or occurrence, is NULL,
   the function also returns NULL.
   Example:
     > SELECT instr('Facebook', 'boo') FROM src LIMIT 1;
     5
     > SELECT instr('CORPORATE FLOOR','OR', 3, 2) FROM src LIMIT 1;
     14  
     > SELECT instr('CORPORATE FLOOR','OR', -3, 2) FROM src LIMIT 1;
     2
   ```
   
   ### How was this patch tested?
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   Tests were added in udf_instr_wrong_args_len2.q, udf_instr_wrong_occurrence.q, and udf_instr.q.




Issue Time Tracking
-------------------

    Worklog Id:     (was: 766984)
    Time Spent: 50m  (was: 40m)

> add position and occurrence to instr()
> --------------------------------------
>
>                 Key: HIVE-25230
>                 URL: https://issues.apache.org/jira/browse/HIVE-25230
>             Project: Hive
>          Issue Type: New Feature
>          Components: UDF
>            Reporter: Quanlong Huang
>            Assignee: Quanlong Huang
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 50m
>  Remaining Estimate: 0h
>
> Current instr() only supports two arguments:
> {code:java}
> instr(str, substr) - Returns the index of the first occurance of substr in str
> {code}
> Other systems (Vertica, Oracle, Impala etc) support additional position and occurrence arguments:
> {code:java}
> instr(str, substr[, pos[, occurrence]])
> {code}
> Oracle doc: [https://docs.oracle.com/database/121/SQLRF/functions089.htm#SQLRF00651]
> It'd be nice to support this as well. Otherwise, it's a SQL difference between Impala and Hive.
>  Impala supports this in IMPALA-3973



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