\documentclass[12pt,a4paper]{article}

\begin{document}
\subsection*{A Demo for a Tabular beside a Tabular inside a Float}

\begin{table}[ht]
\begin{minipage}[b]{0.48\columnwidth}%
\centering
\begin{tabular}{c|c} 
x     & y\\\hline 
rr    & t\\ 
rrrrr & g
\end{tabular}
\caption{a side by side figure/table demo (Table Caption No. 1)}
\end{minipage}%
\hfill%
\begin{minipage}[b]{0.48\columnwidth}%
\centering
\begin{tabular}{c|c} 
x     & y\\\hline 
rr    & t\\ 
rrrrr & g
\end{tabular}
\caption{a side by side figure/table demo (Table Caption No. 2) }
\end{minipage}
\end{table}

\end{document}