Biblatex + biber - Sort citations by report issue

Question

I'm trying to sort some tech report citations from the same year in the bibliography by report issue number, but have got no chance so far, i've even tried adding the month in order to make them sort chronologically but it does not have any effect.

myreferences.bib

@techreport{VanBuskirk2014a,
address = {Sydney},
author = {{Van Buskirk}, Joe and Roxburgh, Amanda and Bruno, Raimondo and Burns, Lucinda},
institution = {National Drug and Alcohol Research Centre},
month = {mar},
number = {2},
pages = {1--14},
title = {{Drugs and The Internet}},
year = {2014}
}

@techreport{VanBuskirk2014b,
address = {Sydney},
author = {{Van Buskirk}, Joe and Roxburgh, Amanda and Bruno, Raimondo and Burns, Lucinda},
institution = {National Drug and Alcohol Research Centre},
month = {sep},
number = {3},
pages = {1--5},
title = {{Drugs and The Internet}},
year = {2014}
}

As i cite the VanBuskirk2014b before the VanBuskirk2014a it's ordered and numbered the wrong way, the september report gets the "a" key and is before in the bibliography whereas the march report gets the "b" key and goes after in the bibliography.

Here a reduced version to illustrate the problem:

test.tex

\documentclass[12pt,a4paper,twoside]{report}
\usepackage[bindingoffset=0.5cm, left=3cm, right=3cm, top=2.5cm, bottom=2.5cm]{geometry}
\usepackage[french]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{csquotes}
\usepackage[backend=biber, style=apa, sortcites=true]{biblatex}
\DeclareLanguageMapping{french}{french-apa}
\setlength\bibitemsep{1.5\itemsep}

\addbibresource{myreferences.bib}

\begin{document}

    \autocite{VanBuskirk2014b}\\

    \autocite{VanBuskirk2014a}

    \printbibliography

\end{document}

Answer 1

You can use the sortyear field to control the sorting manually, use it as sortyear = {<year>-<number>}

@techreport{VanBuskirk2014a,
  address = {Sydney},
  author = {{Van Buskirk}, Joe and Roxburgh, Amanda and Bruno, Raimondo and Burns, Lucinda},
  institution = {National Drug and Alcohol Research Centre},
  month = {mar},
  number = {2},
  pages = {1--14},
  title = {{Drugs and The Internet}},
  year = {2014},
  sortyear = {2014-2},
}

@techreport{VanBuskirk2014b,
  address = {Sydney},
  author = {{Van Buskirk}, Joe and Roxburgh, Amanda and Bruno, Raimondo and Burns, Lucinda},
  institution = {National Drug and Alcohol Research Centre},
  month = {sep},
  number = {3},
  pages = {1--5},
  title = {{Drugs and The Internet}},
  year = {2014},
  sortyear = {2014-3},
}

---

Technically, we could really sort by number as well, but since there is no way to restrict sorting to one type (see the recent Different sorting schemes for different entry types? and how to adapt the sorting of a custom type @standard in using biblatex/biber) that could mess up the sorting for other types that use number.

This is a version of the standard nyvt sorting, where the volume is also considered.

\DeclareSortingScheme{nynot}{
  \sort{
    \field{presort}
  }
  \sort[final]{
    \field{sortkey}
  }
  \sort{
    \field{sortname}
    \field{author}
    \field{editor}
    \field{translator}
    \field{sorttitle}
    \field{title}
  }
  \sort{
    \field{sortyear}
    \field{year}
  }
  \sort{
    \field[padside=left,padwidth=4,padchar=0]{number}
    \literal{0000}
  }
  \sort{
    \field{sorttitle}
    \field{title}
  }
}