On 03/11/2023 07:58, Vikas Rawal wrote:
> Earlier version gives me this:
> \begin{center}
> \begin{tabular}{ll}
> (a,b) & open interval\\\empty
> [0,1] & closed interval\\\empty

It was changed to avoid your inconvenience:
https://list.orgmode.org/874jw2conh.fsf@posteo.net/T/#uOh, wow! Thank you all for having been so considerate of needs of even individual users like this. I did not notice this.
Org mode community does not cease to amaze me. 
> (defun org-export-midrule-filter-latex (row backend info)
>   (replace-regexp-in-string
> "\\(<mid>\\([[:blank:]]+\\&\\)+\\)[[:blank:]]\\\\\\\\" "\\\\midrule" row))
>
> Now my \midrule becomes \midrule[0pt].

Sorry, but your have to adjust the pattern and the replacement string to
allow either optional \empty or [0pt].Done

Thank you once again.

Vikas