Introduce `groupBy` support in SELECT queries.

[alexflav23]

Cassandra 3.0.x introduces support for GROUP BY clauses as part of CQL statements. Add support for such queries in phantom. The details of its usage are found here.

[Rajitha15]

Could you please give some guidelines how to user group by using phantom. i am waiting for this from last week.

[alexflav23]

Hi @Rajitha15 this is currently not supported in phantom and we are working to implement it as part of the next release which should happen shortly. Watch this space for updates.

[Rajitha15]

Could you please update me on this?

[alexflav23]

Hi @Rajitha15 this is being resolved as we speak, and the PR should be ready this weekend. It ended up requiring quite a lot of work and re-write to support properly, but it will be there very shortly, apologies for the delay, we will get you what you need.

[jalaziz]

I'm also interested in support for this. It doesn't appear as if anything has landed yet, though.

[phalodi]

@alexflav23 If its still in progress I can pick this to support groupBy

[binkabir]

Hi @alexflav23 any update on this?