[
https://issues.apache.org/jira/browse/PIG-1922?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13009450#comment-13009450
]
Santhosh Srinivasan commented on PIG-1922:
------------------------------------------
bq. Yes, an filter expression such as (col1 == col2) should not result in error
if either of them is null. But that does not mean that we need to support (col1
== null) in the syntax, as it is unlikely that the user's intention is to get
UNKOWN as the result.
SQL allows the use of = and != with NULL. The resulting value is UNKNOWN.
Granted that we don't have UNKNOWN today. Its something that we should think
about for a few reasons:
1. SQL allows it (to use your argument :)
2. Bailing out with an error will surprise (existing) users.
> null is being treated as string constant in expressions
> -------------------------------------------------------
>
> Key: PIG-1922
> URL: https://issues.apache.org/jira/browse/PIG-1922
> Project: Pig
> Issue Type: Bug
> Affects Versions: 0.8.0, 0.9.0
> Reporter: Thejas M Nair
> Fix For: 0.9.0
>
>
> In following statement, the null gets translated to string constant. The
> statement is invalid, and should result in an error.
> {code}
> fil = filter l by a != null; -- This does not give an error, the correct
> usage is "a is not null"
> fil = filter l by a != adsf; -- this does give an error message saying that
> there is no column asdf
> {code}
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
