Summing time in Org mode in the table

Question

I read about properties in org-mode tables, but either something is broken, or I cannot figure out how to use them. Here is what I tried:

 :PROPERTIES: :COLUMNS: %10item %10start(start){:} %10end(end){:} %10total(total) :END: | | start | end | total | |---+-------+-------+-------| | | 9:30 | 18:45 | 1:10 | | | 9:30 | 18:45 | 1:10 | | | 9:30 | 18:45 | 1:10 | | | 9:30 | 18:45 | 1:10 | | | 9:30 | 18:45 | 1:10 | | | 9:30 | 18:45 | 1:10 | | | 9:30 | 18:45 | 1:10 | |---+-------+-------+-------| | | | | 7:10 | #+TBLFM: @ 2$4..@-1 $4=$3-$2::@>$4=vsum(@ 2$4..@-1 $4) 

The result is obviously absolutely not the one I would expect. I do not think that part of the properties really does something. The result is the same as without it. Put it here to show what I tried.

Answer 1

OK, I found it here: http://orgmode.org/worg/org-hacks.html

Answer: I had to add ;T after the formula, i.e. The final table looks like this:

 | start | end | total | |-------+-------+----------| | 9:30 | 18:45 | 09:15:00 | | 9:30 | 18:45 | 09:15:00 | | 9:30 | 18:45 | 09:15:00 | | 9:30 | 18:45 | 09:15:00 | | 9:30 | 18:45 | 09:15:00 | | 9:30 | 18:45 | 09:15:00 | | 9:30 | 18:45 | 09:15:00 | |-------+-------+----------| | | | 64:45:00 | #+TBLFM: @ 2$3..@-1 $3=$2-$1;T::@>$3=vsum(@ 2$3..@-1 $3);T 

But I would still like to know what these properties do (if at all).

Answer 2

The org-mode COLUMNS property does not apply to tables, but to column views (see http://orgmode.org/manual/Column-view.html ).

What is a column view, imposes a buffer on the table. This table displays the values ​​of the node properties and its child properties.

You can find an example with screenshots in the Org Mode Community .