Get current date in cassandra cql select

Question

In SQL, I am able to do:

select getdate(), getdate() - 7

Which returns the current date as well as current date - 7 days. I want to achieve the same in Cassandra CQL. I tried:

select dateof(now())

But that does not work. It works only on insert and not in select. How can I get the same? Any help would be appreciated.

Answer 1

select dateof(now())

On its own, you are correct, that does not work. But if you have a table that you know only has one row (like system.local):

aploetz@cqlsh:stackoverflow> SELECT dateof(now()) FROM system.local ;

 dateof(now())
--------------------------
 2015-03-26 03:18:39-0500

(1 rows)

Unfortunately, Cassandra CQL does not (yet? CASSANDRA-5505) include support for arithmetic operations, let alone date arithmetic. So subtracting 7 days from that value is something that you would have to do in your application level.

Edit 20200422

The newer syntax uses the toTimestamp() function instead:

aploetz@cqlsh> SELECT toTimestamp(now()) FROM system.local;

 system.totimestamp(system.now())
----------------------------------
  2020-04-22 13:22:04.752000+0000

(1 rows)

Both syntaxes work as of 20200422.