thanks guys, now I see that returning NULL makes sense
On Fri, Nov 2, 2012 at 3:40 PM, Cheolsoo Park <[email protected]> wrote: > Hi Alan, > > Recently, I have seen several similar confusions about nulls in Pig. For > example, here is another discussion: > https://issues.apache.org/jira/browse/PIG-3021. > > We are documenting them, but apparently, many users find it confusing. I am > wondering if there is anything that we can do better. > > Thanks, > Cheolsoo > > 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 > > > > >
