zxo102 ouyang wrote:
> I would like to "group" them into one line with SQL like
>
> 1.5 MPa 2.5 M3 3.5 M3 4.5 t 2008-11-12 12:12:12
Look up the "GROUP BY" clause.
http://www.postgresql.org/docs/current/static/sql-select.html
Note that with timestamps you may have to truncate/round them to the
desired precision, since current versions of PostgreSQL store timestamps
in a floating point format and two timestamps you'd expect to be equal
may not end up being seen as exactly equal.
--
Craig Ringer