There could be inconsistent results: https://issues.apache.org/jira/browse/DRILL-4007
On Mon, Nov 2, 2015 at 8:17 AM, Andries Engelbrecht < aengelbre...@maprtech.com> wrote: > Currently in 1.2 I observe the following. > > 0: jdbc:drill:> select a from dfs.json.`/test.json`; > +-------+ > | a | > +-------+ > | null | > +———+ > > But then flatten produces an error > > 0: jdbc:drill:> select flatten(a) from dfs.json.`/test.json`; > Error: SYSTEM ERROR: ClassCastException: Cannot cast > org.apache.drill.exec.vector.NullableIntVector to > org.apache.drill.exec.vector.complex.RepeatedValueVector > > Ideally both should return similar responses, in most cases it may be > easier to work with a null being returned than no record or an empty > string. Returning [] might be interpreted as a string data type pending > user experience or tools being used?? > > —Andries > > > > > On Oct 31, 2015, at 4:44 PM, Hsuan Yi Chu <hyi...@maprtech.com> wrote: > > > > Hi, > > For example, say, we are querying a field with empty list: > > > > select a from `XXX,json` > > > > { > > a: [] > > } > > > > What is the expected result in the sqlline? Which one of the following > > should it be? > > > > 1. [] > > 2. null > > 3. no record > > > > Thanks. > >