Re: how do i get differences between rows

On Thu, Dec 18, 2003 at 12:21:35 +0000, teknokrat <teknokrat@yahoo.com> wrote:
> I am after an sql query that can give the differnces between consecutive
> timestamp values in the resultset.
> anyone know how to do this?

I think you can do something like the following (untested) on most systems.
select a.stamp - (select max(stamp) from tablename where tablename.stamp < a.stamp) from tablename;

For postgres this (also untested) might be faster if there is an index
on stamp.
select a.stamp - (select stamp from tablename where tablename.stamp < a.stamp order by stamp desc limit 1) from
tablename;

The above relies on timestamps being unique. The difference for the smallest
timestamp will be null.