Biblatex: how to automatically sort numeric citation by year (sortcites=ynt) when bibliography is sorted by citation order (sorting=none)

Question

I'm using numerical citations. In LaTeX (in fact preferentially in LyX), would like to have a multiple-reference citation be sorted by year of publication [1,2,3]. That is, 3 was published after 2 and 1.

And later in the document if I cite [8,3,24] it should be that 24 was published after 3 and 3 after 8.

However, in the bibliography, I would like these numeric items to be sorted of course by number 1, 2, 3...

There are many questions with similar combinations, but I cannot find this one.

Here's my attempt, using biber

    \documentclass[]{article}
\begin{filecontents*}{references.bib}
@misc{first,
  title={Reference A},
  author={Alice},
  year={1980},
}
@misc{second,
  title={Reference B},
  author={Bob},
  year={2000},
}
@misc{third,
  title={Reference C},
  author={Caleb},
  year={1970},
}
\end{filecontents*}
\usepackage[
sortcites=ynt,
sorting=none,
    backend=biber,
    hyperref=true,
    firstinits=true,
    maxbibnames=99,
    ]{biblatex}
\addbibresource{references.bib}
\begin{document}
First: \cite{third,first,second} 
Second: \cite{second,first}
\printbibliography
\end{document}

The second citation should be 2,3, since Ref A was published earlier.

Answer 1

In order to have full control over the sorting of separate \cite calls, you may want to define a new sorting scheme that takes into account citation order and publication date.

\documentclass[]{article}
\usepackage[
  backend=biber,
  sortcites=true,
  sorting=noney,
  giveninits=true,
  maxbibnames=99,
]{biblatex}
\DeclareSortingTemplate{noney}{
  \sort{\citeorder}
  \sort{
    \field{sortyear}
    \field{year}
  }
  \sort{\intciteorder}
}
\begin{filecontents}{\jobname.bib}
@misc{first,
  title={Reference A},
  author={Alice},
  year={1980},
}
@misc{second,
  title={Reference B},
  author={Bob},
  year={2000},
}
@misc{third,
  title={Reference C},
  author={Caleb},
  year={1970},
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
First: \cite{third,second,first} 
Second: \cite{second,first}
\printbibliography
\end{document}

Note that the sortcites option expects a boolean value (but any non-true value is treated as false). So sortcites=ynt, is treated as sortcites=false,.

---

\inciteorder was added in biblatex v3.18 (2022-06-22) and will therefore be available on all up-to-date TeX systems. If you cannot update, you can try to remove the line \sort{\intciteorder} from the definition of \DeclareSortingTemplate{noney} above. (This appears to work in the MWE with biblatex v3.16 from Overleaf's TeX Live 2021. But it may not work as intended in older systems, since there were changes to Biber's handling of sorting=none, not too long ago https://github.com/plk/biber/issues/404.)