Re: calculating elapsed times between timestamps

rhubbell wrote:
> (posted on novice too, no idea what difference is between lists)
>
> I have been trying to do this and have been unsuccessful so far.
>
> I have a table:
>
> perf:
> timestamp   = timestamp with time zone
> timeelapsed = numeric
> bobble      = text
>
> timeelapsed records are the time elapsed metric in seconds.
>
> e.g. 0.350058078765869
>
> Typical scenario is that I'll have multiple entries where timeelapsed
> is greater than some value and will be greater than that value for
> some time interval.
>
>
> I want to find the length of those intervals.
>
> select timestamp, timeelapsed, bobble from perf where bobble like "pokerflat"
> and timeelapsed > 0.4;
>
> The records returned by that query will have an oldest and newest timestamp for
> which I would like to calculate the interval.
>
I'm not real clear on what you are asking here  with oldest and newest
timestamps and getting the interval, please clarify
> I found lots of examples of doing arithmetic on timestamps but I never saw
> any extracting data from a table.  All the examples I found were using now()
> or current_date + 3 or the like.
>
Just substitute current_date or now() appears in the examples with the
column name
> Do aggregate function work on time data?
>

For date time function go here
http://www.postgresql.org/docs/8.3/static/functions-datetime.html