Stamatis Zampetakis created HIVE-27586:
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Summary: Parse dates from strings ignoring trailing (potentialy)
invalid chars
Key: HIVE-27586
URL: https://issues.apache.org/jira/browse/HIVE-27586
Project: Hive
Issue Type: Improvement
Components: HiveServer2
Affects Versions: 4.0.0-beta-1
Reporter: Stamatis Zampetakis
Assignee: Stamatis Zampetakis
The goal of this ticket is to extract and return a valid date from a string
value when there is a valid date prefix in the string.
The following table contains a few illustrative examples highlighting what
happens now and what will happen after the proposed changes to ignore trailing
characters. HIVE-20007 introduced some behavior changes around this area so the
table also displays what was the Hive behavior before that change.
||ID||String value||Before HIVE-20007||Current behavior||Ignore trailing chars||
|1|2023-08-03_16:02:00|2023-08-03|null|2023-08-03|
|2|2023-08-03-16:02:00|2023-08-03|null|2023-08-03|
|3|2023-08-0316:02:00|2024-06-11|null|2023-08-03|
|4|03-08-2023|0009-02-12|null|0003-08-20|
|5|2023-08-03 GARBAGE|2023-08-03|2023-08-03|2023-08-03|
|6|2023-08-03TGARBAGE|2023-08-03|2023-08-03|2023-08-03|
|7|2023-08-03_GARBAGE|2023-08-03|null|2023-08-03|
This change partially (see example 3 and 4) restores the behavior changes
introduced by HIVE-20007 and at the same time makes the current behavior of
handling trailing invalid chars more uniform.
This change will have an impact on various Hive SQL functions and operators
(+/-) that accept dates from string values. A partial list of affected
functions is outlined below:
* CAST (V AS DATE)
* CAST (V AS TIMESTAMP)
* TO_DATE
* DATE_ADD
* DATE_DIFF
* WEEKOFYEAR
* DAYOFWEEK
* TRUNC
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