foobar.tex

\documentclass{article}
\usepackage{caption}
\usepackage{longtable}
\usepackage{booktabs}
\begin{document}
%\begingroup
\begin{table}
\captionof{table}{First table}\label{first}
\begin{longtable}{cc}
  x&y\\
\end{longtable}
% \endgroup
\end{table}
%\begingroup
\begin{table}
\captionof{table}{Second table}\label{second}
\begin{longtable}{cc}
  x&y\\
\end{longtable}
%\endgroup
\end{table}
\end{document}

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%%% mode: latex
%%% TeX-master: t
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