# Biblatex inherits publication date from urldate in bibliography

Using biber, I do not encounter this issue but I want to use bibtex for the backend option.

I have an "online" bibitem with an accessed on date but no publication date. I want the output to be along the lines of AUTHOR (n.d.) URL [Accessed on: dd/mm/year].

I can only find a way to do this by clearing the urlyear, which I don't want to do. Furthermore, this thread suggests setting the year to the text "n.d." however this generates a warning about issues with sorting which I would like to avoid.

MWE:

\documentclass[british]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{csquotes}

\usepackage[style=authoryear, backend=biber, urldate=long, dateabbrev=false]{biblatex}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@online{appleby,
author  = {Humphrey Appleby},
date = {},
title   = {On the Importance of the Civil Service},
url     = {https://example.com/gov/sir-humphrey/importance-civil-service},
urldate = {2018-08-23},
}
\end{filecontents}

\begin{document}
\nocite{*}
\printbibliography
\end{document}


I would like to display n.d. or similar in the empty brackets. I could do this either by:

• Preventing the publication date being inherited from the access date.
• Manually setting the date to be "null" somehow, but doing this it gives ("null") as the date in the ways that I have tried.

Thanks.

If you must use bibtex as your backend, then you can specify year = {nodate} instead of using the date field.

Aside: If you use biber as backend, then I think the easiest option is just to alter the definition of \DeclareLabeldate to remove urldate from the list of allowable fields. e.g.,

\DeclareLabeldate{%
\field{date}
\field{year}
\field{eventdate}
\field{origdate}
\literal{nodate}
}


# MWE using bibtex as backend

\documentclass[british]{article}
\usepackage{babel}
\usepackage{csquotes}

\usepackage[style=authoryear, backend=bibtex, urldate=long, dateabbrev=false]{biblatex}

\begin{filecontents}[overwrite]{\jobname.bib}
@online{appleby,
author  = {Humphrey Appleby},
year    = {nodate},
title   = {On the Importance of the Civil Service},
url     = {https://example.com/gov/sir-humphrey/importance-civil-service},
urldate = {2018-08-23},
}
\end{filecontents}