# How to put two tables in a table* element so that the tables appear side by side in a two column layout scientific paper?

This is related to How to make a figure span on two columns in a scientific paper?

In a table* element, I want to put two \tabular{} elements, and get them appear side by side. I will then need to caption them as (a) and (b) and create labels (for references in the text) and so forth. If I just use the table* element, the tables appear below each other and are centred across the two columns.

EDIT: In response to TH: This is what I tried. Both tables still appear on the right column.

\begin{table*}
\subfloat[Before processing]{
\begin{tabular}{|c|c|c|c|c|}
\hline
Year & Month & Country & State & Impressions\tabularnewline
\hline
\hline
2007 & JAN & IN & TN & 3\tabularnewline
\hline
2007 & JAN & IN & TN & 1\tabularnewline
\hline
\end{tabular}
}

\begin{table}
\subfloat[After processing]{
\begin{tabular}{|c|c|c|c|c|}
\hline
Year & Month & Country & State & Impressions\tabularnewline
\hline
\hline
2007 & JAN & IN & TN & 7\tabularnewline
\hline
2007 & FEB & IN & KA & 13\tabularnewline
\hline
\end{tabular}
}
\caption{overall}
\end{table*}
• I've found it easier to use the multicol package, stop the multicol environment, set the tables as you wish (in 1 column mode) then start the multicol environment again. – Mica Nov 29 '10 at 22:25

You should use the subfig package.

\begin{table*}
\subfloat[First caption]{\begin{tabular}{...}...\end{tabular}}
\subfloat[Second caption]{\begin{tabular}{...}...\end{tabular}}
\caption{Overall caption}
\end{table*}

This can be used in conjunction with the floatrow package. See the subfig documentation for an example that aligns captions using floatrow.

EDIT:
Your example has an extra \begin{table} that doesn't belong. It also has a blank line which causes TeX to start a new paragraph which is why one table appears on top of the other.

Here's a complete example where I've also cleaned up your tables following the guidelines given in the documentation to the booktabs package.

\documentclass[twocolumn]{article}
\usepackage{subfig}
\usepackage{booktabs}
\begin{document}
\begin{table*}
\subfloat[Before processing]{
\begin{tabular}{ccccc}
\toprule
Year & Month & Country & State & Impressions\\
\midrule
2007 & JAN & IN & TN & 3\\
2007 & JAN & IN & TN & 1\\
\bottomrule
\end{tabular}
}%
\hfill
\subfloat[After processing]{
\begin{tabular}{ccccc}
\toprule
Year & Month & Country & State & Impressions\\
\midrule
2007 & JAN & IN & TN & 7\\
2007 & FEB & IN & KA & 13\\
\bottomrule
\end{tabular}
}
\caption{overall}
\end{table*}
\end{document}
• Thanks for your effort, but the tables still appear below each other (and its not because of lack of space - if I make them as separate tables, they do appear on different columns, side-by-side). – donatello Nov 28 '10 at 17:17
• The »subfig« package isn't maintained any more thus not suggestive. »floatrow« also masters sub-figures on its own. So I see no necessity for a conjunction. – Thorsten Donig Nov 28 '10 at 17:47
• @donatello: I think you're going to need to provide a minimal example at this point. – TH. Nov 28 '10 at 18:27
• @Thorsten: My version of subfig.sty lists Steven Douglas Cochran as the maintainer. ctan.org/pkg/subfig lists Steven as in inactive maintainer and Vafa Khalighi as an active maintainer. Further, the floatrow documentation explicitly mentions working with subfig. – TH. Nov 28 '10 at 18:29
• Hey please see my edit in the q. I've provided an example. – donatello Nov 28 '10 at 18:54

Complying with the request of TH., here comes an example that uses the »subcaption« package (shipped with caption). The tables will appear on top of page 3 of the resulting document.

\documentclass[11pt,a4paper,twocolumn,english]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage[font=small,labelfont=bf,tableposition=top]{caption}
\usepackage[font=footnotesize]{subcaption}
\usepackage{booktabs}
\usepackage{blindtext}

%\DeclareCaptionSubType*[arabic]{table}
%\captionsetup[subtable]{labelformat=simple,labelsep=colon}

\title{Two tables side by side in a \texttt{table*} environment within a two column document}
\author{Donatello}

\begin{document}
\maketitle

\blinddocument

\begin{table*}
\caption{Dummy tables}\label{tab:dummy}
\centering
\begin{subtable}[t]{\columnwidth}
\caption{Dummy sub-table}\label{subtab-1:dummy}
\centering
\begin{tabular}{ccc}\toprule
Some values & Some values & Some values \\
Some values & Some values & Some values \\
Some values & Some values & Some values \\ \bottomrule
\end{tabular}
\end{subtable}
\hfill
\begin{subtable}[t]{\columnwidth}
\caption{Dummy sub-table}\label{subtab-2:dummy}
\centering
\begin{tabular}{ccc}\toprule
Some values & Some values & Some values \\
Some values & Some values & Some values \\
Some values & Some values & Some values \\ \bottomrule
\end{tabular}
\end{subtable}
\end{table*}

\blinddocument
\end{document}

I have chosen \columnwidth as width for the two subtable environments and centered the two sub-tables optically in the respective column.

The commented lines shall serve as a possible example for redefining the numbering of the subtables.

As always, the blindtext package is only for creating dummy text thus not part of the solution.