I just play around a bit and found a solution to show series "a of x"
But this maybe a performance issue and should not be used for a big library or only for subsets and in (normally) hidden columns.
There are a lot of example in the forum for number-format tweaking, if needed.
1. Preferences - Advanced - Tweaks - set "allow_template_database_functions_in_composit es = True" (only available with Calibre 6 and up)
2. Add column - "column built from other columns" and output "text"
3. Copy this code into the column template:
Code:
program:
# Returns the series_index together with the last number in a series (or nothing for book with no series), e.g. [2/5]
if field('series') then
this_series = field('series');
books_in_series = book_values('title', 'series:="' & this_series & '"', ',', 0);
highest_series_num = 0;
for title in books_in_series:
title_index = book_values('series_index', 'title:="' & title & '"', ',', 0);
if title_index > highest_series_num then
highest_series_num = title_index
fi
rof;
series_idx_max = "["&field('series_index')&"/"&highest_series_num&"]"
else
series_idx_max = ""
fi;
output = series_idx_max