org-mode agenda: sort items with plain time stamp before scheduled tasks

Question

I have an org-file which might look like the following:

* Appointments
** Meet someone important
<2018-02-15 Thu 08:00-09:00>

* Discussions
** TODO Discuss something with someone
    SCHEDULED: <2018-02-15 Thu 08:00-09:00>

Generating the agenda results in something like

8:00-9:00 Scheduled: TODO Discuss something with someone
8:00-9:00 Meet someone important

Is there a simple way to change the sorting of the agenda to sort entries with a plain time stamp before scheduled items, that is I would the agenda prefer to look like

8:00-9:00 Meet someone important
8:00-9:00 Scheduled: TODO Discuss something with someone

I had a look at the documentation for org-agenda-sorting-strategy but this looked quite complicated and I could not figure out how to achieve the desired result.

Answer 1

It's a little hard to figure out org-agenda-sorting-strategy the first time around. If you look at the value (say, with C-h v), it's a list of lists. The individual lists describe the sorting to be used in a specific "context", like agenda or todo for different kinds of agenda views.

The default value is:

((agenda habit-down time-up priority-down category-keep)
  (todo priority-down category-keep)
  (tags priority-down category-keep)
  (search category-keep))

So for the agenda view, it will sort first to put habits at the end (that's what the -down means for it), then entries with time of day first, priority in decreasing order, and keep the default order of categories.

So what you want sounds like ts-up, to keep active timestamps early first. Therefore, we want the first value to look like:

(agenda ts-up habit-down time-up priority-down category-keep)

The easiest way is to customize the variable and add the ts-up there.