hadoop-hive-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Ashish Thusoo (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-179) SUBSTR function should work like other databases
Date Sat, 10 Jan 2009 02:26:01 GMT

    [ https://issues.apache.org/jira/browse/HIVE-179?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662606#action_12662606
] 

Ashish Thusoo commented on HIVE-179:
------------------------------------

The actual error is happening between the map and reduce boundary of the second map reduce
job. The ddl for the dynamic serde that is used to serialize data at this boundary is double,
long where as the output generated is long, double as seen in the plan.


> SUBSTR function should work like other databases
> ------------------------------------------------
>
>                 Key: HIVE-179
>                 URL: https://issues.apache.org/jira/browse/HIVE-179
>             Project: Hadoop Hive
>          Issue Type: Bug
>          Components: Query Processor
>            Reporter: David Phillips
>            Assignee: David Phillips
>            Priority: Critical
>         Attachments: hive-substr.patch
>
>
> Positions start at 1, not 0.  Negative positions start at the end of the string and count
backwards.
> Oracle returns null for lengths less than 1 or non-existent substrings (any empty strings
are null).  MySQL and PostgreSQL return empty strings, never null.  PostgreSQL errors for
negative lengths.  I suggest we follow the MySQL behavior.
> Oracle treats position 0 the same as 1.  Perhaps we should too?
> {noformat}
>  SUBSTR('ABCDEFG',3,4): CDEF
> SUBSTR('ABCDEFG',-5,4): CDEF
>    SUBSTR('ABCDEFG',3): CDEFG
>   SUBSTR('ABCDEFG',-5): CDEFG
>      SUBSTR('ABC',1,1): A
> MySQL:
>      SUBSTR('ABC',0,1): <empty>
>      SUBSTR('ABC',0,2): <empty>
>      SUBSTR('ABC',1,0): <empty>
>     SUBSTR('ABC',1,-1): <empty>
> Oracle:
>      SUBSTR('ABC',0,1): A
>      SUBSTR('ABC',0,2): AB
>      SUBSTR('ABC',1,0): <null>
>     SUBSTR('ABC',1,-1): <null>
> {noformat}

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message