Hi Marc, On Tue, Apr 21, 2020 at 4:20 PM Marc Richter <m...@marc-richter.info> wrote:
> The database is already of round about 260 GB in size. > I now need to know what is the most recent entry in it; the correct > column to learn this would be "insertdate". > > In SQL I would do something like this: > > SELECT insertdate FROM tagdata.central > ORDER BY insertdate DESC LIMIT 1; > > In CQL, however, I just can't get it to work. > As others have already pointed out, you need to design your data model to support the queries you need. CQL is not SQL and you cannot query the data in arbitrary ways if your data model does not support it, at least not efficiently. Although the context is DynamoDB, I have found the following presentation by Rick Houlihan to be pretty good on this topic and more or less applicable to Cassandra. The part about "NoSQL data modeling" starts at 22:45 mark: https://www.youtube.com/watch?v=HaEPXoXVf2k&feature=youtu.be&t=1363 Hope this helps! - Pekka
