On Wed, Nov 12, 2008 at 3:59 AM, zxo102 ouyang <[EMAIL PROTECTED]> wrote:
> Hi everyone,
> My data with same timestamp "2008-11-12 12:12:12" in postgresql are as
> follows
>
> rowid data unitchannel create_on
> ---
On Thu, Nov 13, 2008 at 06:39:47PM -0800, Eus wrote:
> Isn't that something like this is better handled at the application level
> instead of the DB level?
>
> IOW, isn't that the cost of doing the query above far more expensive than
> doing a little coding at the application level?
That's some
Hi Ho!
--- On Thu, 11/13/08, Brent Wood <[EMAIL PROTECTED]> wrote:
> You need to use a self relation, not a group by, as no data
> are being aggregated into a new single value, which is what
> the group by achieves.
>
> This joins a table to itself, so that columns in it can be
> replicated. The
On Thu, Nov 13, 2008 at 06:56:43AM +1300, Brent Wood wrote:
> You need to use a self relation, not a group by, as no data are
> being aggregated into a new single value, which is what the group by
> achieves.
It's perfectly possible to use a GROUP BY clause; all rows from one time
period want to b
You need to use a self relation, not a group by, as no data are being
aggregated into a new single value, which is what the group by achieves.
This joins a table to itself, so that columns in it can be replicated. The key
is that the where clause in each case
needs to just select one channel, so
zxo102 ouyang wrote:
> I would like to "group" them into one line with SQL like
>
>1.5 MPa 2.5M3 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 trunca
Hi everyone,
My data with same timestamp "2008-11-12 12:12:12" in postgresql are as
follows
rowid data unitchannel create_on
--
11.5 MPa channel1 2008-11-12 12:12:12
2
