Sorry I didn't get it. I'll completely remove
http://drill.apache.org/docs/json-data-model/#empty-array. Thanks guys.
Kristine Hahn
Sr. Technical Writer
415-497-8107 @krishahn skype:krishahn
On Mon, Oct 19, 2015 at 12:59 PM, John Omernik <j...@omernik.com> wrote:
> Awesome that worked.
>
> *The documentation should probably be updated on the array stuff, it's not
> accurate as it pertains to empty arrays.
>
>
>
> On Mon, Oct 19, 2015 at 2:52 PM, Andries Engelbrecht <
> aengelbre...@maprtech.com> wrote:
>
> > Use where a[0] is not null
> >
> > 0: jdbc:drill:> select * from `./array.json`;
> > +----+--------+
> > | b | a |
> > +----+--------+
> > | 1 | [] |
> > | 3 | [1,2] |
> > +----+--------+
> > 2 rows selected (0.13 seconds)
> > 0: jdbc:drill:> select * from `./array.json` where a[0] is not null;
> > +----+--------+
> > | b | a |
> > +----+--------+
> > | 3 | [1,2] |
> > +----+--------+
> > 1 row selected (0.151 seconds)
> >
> > —Andries
> >
> >
> > > On Oct 19, 2015, at 12:32 PM, John Omernik <j...@omernik.com> wrote:
> > >
> > > Well you are in a sense confirming my suspicions that an empty array,
> as
> > > specified in the Docs as "error causing" doesn't actually cause an
> error,
> > > and that is expected. That is, empty arrays are not the big meanies
> that
> > > the docs make them out to be (my results are the same as your, that is,
> > no
> > > errors).
> > >
> > > I like the flatten approach, but is there a simple way to say select *
> > from
> > > dfs.tdunning.`x.json` where
> > >
> > > a is not empty
> > >
> > > or
> > >
> > > size(a) == 0
> > >
> > > or
> > >
> > > a != []
> > >
> > >
> > > I guess some functions for working with arrays would be handy. I'll
> play
> > > with flatten to see if it gives me what I am looking for, but are there
> > > other ways to play with arrays (now that I confirm that empty arrays
> > aren't
> > > evil)
> > >
> > > John
> > >
> > >
> > > On Mon, Oct 19, 2015 at 1:40 PM, Ted Dunning <ted.dunn...@gmail.com>
> > wrote:
> > >
> > >> John,
> > >>
> > >> I don't understand what you are seeing. Here is what I am seeing (and
> > >> hopefully you can tell what I am missing).
> > >>
> > >> First the input is:
> > >>
> > >> $ cat x.json
> > >> {"b":1, "a":[] }
> > >> {"a":[1,2], "b":3}
> > >>
> > >> And then with this input, I get this:
> > >>
> > >> 0: jdbc:drill:> select * from dfs.tdunning.`x.json`;
> > >> +----+------------+
> > >> | b | a |
> > >> +----+------------+
> > >> | 1 | [] |
> > >> | 3 | ["1","2"] |
> > >> +----+------------+
> > >> 2 rows selected (0.443 seconds)
> > >> 0: jdbc:drill:> select a,b from dfs.tdunning.`x.json`;
> > >> +------------+----+
> > >> | a | b |
> > >> +------------+----+
> > >> | [] | 1 |
> > >> | ["1","2"] | 3 |
> > >> +------------+----+
> > >> 2 rows selected (0.473 seconds)
> > >> 0: jdbc:drill:> select flatten(a),b from dfs.tdunning.`x.json`;
> > >> +---------+----+
> > >> | EXPR$0 | b |
> > >> +---------+----+
> > >> | 1 | 3 |
> > >> | 2 | 3 |
> > >> +---------+----+
> > >> 2 rows selected (0.499 seconds)
> > >>
> > >>
> > >> On Mon, Oct 19, 2015 at 7:03 AM, John Omernik <j...@omernik.com>
> wrote:
> > >>
> > >>> In https://drill.apache.org/docs/json-data-model/ there is a section
> > >> that
> > >>> goes as laid out below. This is actually not occurring for me. I
> > have a
> > >>> json dump from Mongo that has a field called tags where many records
> > have
> > >>> "tags":[] and it's outputting that without error. (It just shows []
> as
> > >> the
> > >>> output).
> > >>>
> > >>> So, my question is this... based on the documentation, what I am
> seeing
> > >> is
> > >>> NOT expected, is it a miss on the docs, or something that is fixed in
> > the
> > >>> 1.2 release that I have?
> > >>>
> > >>> If it is fixed so we can have empty arrays in a field like tags, is
> it
> > >>> possible there are some functions I can use to determine if that
> field
> > is
> > >>> empty? i.e. if isemptyarray(tags) returns true if empty or perhaps
> get
> > me
> > >>> the length said array? These functions would be very valuable in
> > >> queries
> > >>> (if the empty arrays thing is not a weird quirk I am seeing).
> > >>>
> > >>> Empty array
> > >>>
> > >>> Drill cannot read an empty array, shown in the following example, and
> > >>> attempting to do so causes an error.
> > >>>
> > >>> { "a":[] }
> > >>>
> > >>> Workaround: Remove empty arrays.
> > >>>
> > >>
> >
> >
>
