This puzzler is not a clean SQL puzzler, as it is related not only to the SQL function now(), but to a PHP function time() too. Are you accessing PostgreSQL from PHP? In that case you should solve this puzzler easily ;-)
Partitioning may be used as a quite elegant solution of a wide variety of problems - distributing the table to multiple drives (if you don't want to use a traditional RAID), effective removal of archive data (without DELETE), etc. It may be automatically realized using triggers or rules. Lets see a puzzler related to partitioning realized with rules.
Last week I've posted a first puzzler related to generating random numbers or rather selecting random rows in PostgreSQL, believing that it's first and maybe the last puzzler for a long time. Well, today I've found a similar feature in Oracle - so lets begin!
First (and so far last) SQL puzzler, related to some basic concepts from relational databases, as for example primary keys. Note - this puzzler is quite closely adherent to PostgreSQL database (it uses some PL/pgSQL functions to generate example data, but that's not all).
