Add comma between author and year with et al

Question

I am using biblatex with style=authoryear and maxcitenames=2. For a reference with more than two authors \cite command produces

Erkus et al. 2010

and \textcite command produces

Erkus et al. (2010)

I would like to add a comma between et al. and the year only for the \cite command (but not for the \textcite command), i.e.,

Erkus et al., 2010

Erkus et al. (2010)

\renewcommand*{\nameyeardelim}{\addcomma\space}

Works only for single author references ( see this question), but does not work with the shorthand use of et al. for references with more than two authors. I do not want to use \DefineBibliographyStrings to redefine andothers and add comma after et al. since it also adds comma to \textcite citation, which I don't want.

I tried the following (see this question) but did not work:

\renewcommand*{\nameyeardelim}{%
     \ifnumgreater{\value{listcount}}{2}{\nameyeardelim}{\addcomma\space}%
     \ifnumequal{\value{listcount}}{1}{\nameyeardelim}{\addcomma\space}%
}

Answer 1

You can achieve this by setting the natbib=true option in the \usepackage for biblatex.

MWE:

\begin{filecontents*}{database.bib}
@inproceedings{erkus_2010,
  title = {Title},
  booktitle = {Book Title},
  date = {2010},
  author = {Erkus, Firstname and Lastname, Firstname and Lastname Anotherfirstname}
}
\end{filecontents*}

\documentclass[]{article}

\usepackage{filecontents}

\usepackage[style=authoryear, maxcitenames=2, backend=biber, natbib=true] {biblatex}

\addbibresource{database.bib}

\begin{document}

Cite: \cite{erkus_2010}

Textcite: \textcite{erkus_2010}

\end{document}

Which produces:

Answer 2

\renewcommand*{\nameyeardelim}{\addcomma\space}should work for regardless of whether you cite one or more authors. In recent versions of biblatex nameyeardelim is a context-sensitive delimiter, which means you should use \DeclareDelimFormat to modify it

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

\usepackage[style=authoryear, maxcitenames=2, backend=biber]{biblatex}

\DeclareDelimFormat{nameyeardelim}{\addcomma\space}

\addbibresource{biblatex-examples.bib}

\begin{document}
\cite{sigfridsson,aksin,herrmann,nussbaum}

\textcite{sigfridsson,aksin,herrmann,nussbaum}

\printbibliography
\end{document}

If you take a look at blx-natbib.def, you'll see that it uses exactly the same command as suggested here. That's why natbib=true (as suggested in Alex' answer) also produces the desired comma.