# How can I name multiple columns in a table?

\begin{table}
\begin{center}
\caption{Types of Aggregation}
\label{table:my_label1}

\begin{tabular}{|c |c| c| c|}
\multicolumn{4}{c}{}{$\overbrace{\rule{12.5em}{0pt}}^{Spatial Aggregation}$}\\
\hline

Meters & $time_1$ & $time_2$ & $time_3$ \\ [0.5ex]
\hline

$SM_{1}$ & $R_{1,1}$ & $R_{1,2}$ & $R_{1,3}$\\
\hline
$SM_2$  & $R_{2,1}$ & $R_{2,2}$ & $R_{2,3}$\\
\hline
$SM_3$  & $R_{3,1}$ & $R_{3,2}$ & $R_{3,3}$\\
\hline

\end{tabular}
\end{center}
\end{table}


I want to name the 2nd, 3rd and 4th column using \overbrace. How can I do that?

Welcome to TeX-SE! Assuming you want something similar to your code, you could use

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{table}
\centering
\caption{Types of Aggregation}
\label{table:my_label1}
\begin{tabular}{|c |c| c| c|}
\multicolumn{1}{c}{}&
\multicolumn{3}{c}{$\overbrace{\rule{9.5em}{0pt}}^{\text{Spatial Aggregation}}$}\\
\hline
Meters & $\text{time}_1$ & $\text{time}_2$ & $\text{time}_3$ \\ [0.5ex]
\hline
$SM_{1}$ & $R_{1,1}$ & $R_{1,2}$ & $R_{1,3}$\\
\hline
$SM_2$  & $R_{2,1}$ & $R_{2,2}$ & $R_{2,3}$\\
\hline
$SM_3$  & $R_{3,1}$ & $R_{3,2}$ & $R_{3,3}$\\
\hline
\end{tabular}
\end{table}
\end{document}


You can use \downbracefill, similar to what is suggested in Using \underbrace with table columns:

\documentclass{article}

\begin{document}

\begin{tabular}{| *{4}{c |} }
\multicolumn{1}{c}{} & \multicolumn{3}{c}{\small Spatial aggregation} \\[-.3\normalbaselineskip]
\multicolumn{1}{c}{} & \multicolumn{3}{c}{\downbracefill} \\
\hline
Meters & $time_1$ & $time_2$ & $time_3$ \\
\hline
$SM_1$ & $R_{1,1}$ & $R_{1,2}$ & $R_{1,3}$  \\
\hline
$SM_2$ & $R_{2,1}$ & $R_{2,2}$ & $R_{2,3}$  \\
\hline
$SM_3$ & $R_{3,1}$ & $R_{3,2}$ & $R_{3,3}$  \\
\hline
\end{tabular}

\end{document}