[emacs-berlin] July 2025 Meetup is next week

[Tilmann Singer]

Hi everyone, hi jman,

Seconded, it was a nice meeting yesterday, thanks everyone for
attending, and the remote people for bearing with us during the slow
setup.

Regarding the question how aggregate an org-table: the approach to use
orgtbl-aggregate seemed obvious at first but failed because I
misunderstood how it works, and I'm not fluent enough in emacs date
calculations. I've asked on the project's GitHub and got a more than
detailed reply: https://github.com/tbanel/orgaggregate/issues/24

The simple approach is to add a computed column for just the month and
aggregate by that:

#+name: distances
| Date             |   KM | Month |
|------------------+------+-------|
| [2025-07-16 Wed] | 28.6 |     7 |
| [2025-07-17 Thu] |    6 |     7 |
| [2025-07-18 Fri] |   12 |     7 |
| [2025-07-19 Sat] |   18 |     7 |
| [2025-07-20 Sun] |   18 |     7 |
| [2025-07-21 Mon] |   10 |     7 |
| [2025-07-22 Tue] |   14 |     7 |
| [2025-07-23 Wed] |    9 |     7 |
| [2025-08-01 Fri] |   12 |     8 |
| [2025-08-02 Sat] |   12 |     8 |
| [2025-08-03 Sun] |    9 |     8 |
#+TBLFM:$3=month($1)

#+BEGIN: aggregate :table "distances" :cols "Month vsum(KM)"
| Month | vsum(KM) |
|-------+----------|
|     7 |    115.6 |
|     8 |       33 |
#+END:

To also consider the year you could add another column and aggregate by
the two columns Year and Month, or precompute a string like "2025-07".

See the GitHub issue for a more sophisticated solution.

And of course there's the completely different approach to use
properties and dynamic blocks that Sebastian suggested.


cheers, Til
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