Q:

How can I have two tables side by side?

Suppose I have two tables that don't have many columns (3, for example). How can I position them side by side?

A:

Just put two tabular environments side by side. Add spacing as desired.
\begin{tabular}{ccc}
\hline
a&b&c\\
\hline
\end{tabular}
\quad
\begin{tabular}{ccc}
\hline
d&e&f\\
\hline
\end{tabular}

If you want to use subfig because you want them to have separate captions, then that is simple as well.
\subfloat[caption]{\begin{tabular}{...}...\end{tabular}}
\subfloat[caption]{\begin{tabular}{...}...\end{tabular}}

If you want two tables that are independent, and thus don't want to use \subfloat, you can use \parbox.
\begin{table}
\parbox{.45\linewidth}{
\centering
\begin{tabular}{ccc}
\hline
a&b&c\\
\hline
\end{tabular}
\caption{Foo}
}
\hfill
\parbox{.45\linewidth}{
\centering
\begin{tabular}{ccc}
\hline
d&e&f\\
\hline
\end{tabular}
\caption{Bar}
}
\end{table}

This is basically the same as before just that I've centered each tabular in a \parbox with an included caption and wrapped the whole thing in a table.

A:

If you want two tabulars next to each other in a (floating) table environment, then you can use minipages

\begin{table}[!htb]
    \caption{Global caption}
    \begin{minipage}{.5\linewidth}
      \caption{}
      \centering
        \begin{tabular}{ll}
            1 & 2
        \end{tabular}
    \end{minipage}%
    \begin{minipage}{.5\linewidth}
      \centering
        \caption{}
        \begin{tabular}{ll}
            3 & 4
        \end{tabular}
    \end{minipage} 
\end{table}

Loading the caption package will allow easy customization, and will remove the : when the caption is empty.
If you'd like 'sub'tables, then you can use the subcaption package which introduces the subtable environment (and a lot more); the subtable environment takes the same mandatory and optional arguments as the minipage

\documentclass{article}
\usepackage{subcaption}
\begin{document}

\begin{table}[!htb]
    \caption{Global caption}
    \begin{subtable}{.5\linewidth}
      \centering
        \caption{}
        \begin{tabular}{ll}
            1 & 2
        \end{tabular}
    \end{subtable}%
    \begin{subtable}{.5\linewidth}
      \centering
        \caption{}
        \begin{tabular}{ll}
            3 & 4
        \end{tabular}
    \end{subtable} 
\end{table}

\end{document}

Note that in both cases I've used a % at the end of the environment to stop overfull hboxes  from the additional space added by the minipage.

A:

Ceteris paribus, you might consider the subfig package. It is suitable for subtables and subfigures and combinations of these.  For myself, I've managed much mileage from it.

