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Pig >> mail # user >> CONCAT(null, "something") == NULL ?

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Re: CONCAT(null, "something") == NULL ?
Hi Alan,

Recently, I have seen several similar confusions about nulls in Pig. For
example, here is another discussion:

We are documenting them, but apparently, many users find it confusing. I am
wondering if there is anything that we can do better.


On Fri, Nov 2, 2012 at 3:33 PM, Alan Gates <[EMAIL PROTECTED]> wrote:

> To give some context, the null semantics in Pig follow SQL's.  In SQL,
> null is viral, so any operation with null results in null.  The idea is
> that null means unknown, not empty.  So concat('x', unknown) = unknown.
> Alan.
> On Nov 2, 2012, at 3:09 PM, Yang wrote:
> > looks a more intuitive result should be "something" , right?
> >
> > but on my system it gave null