Multiple multi-columns in a table

Question

I would like to create a table like this:

         +------------+----------+
         |      M1    |     M2   |
+--------+------+-----+------+---+
|  Prog  |   E  |  S  |  E   | S | 
+--------+------+-----+------+---+
| P1     |  1   |  5  | 0.6  | 10|
| P2     |  2   |  7  | 2    | 6 |
+--------+------+-----+------+---+

Based on the examples, I have written this

\begin{document}
    \begin{table}
        \centering
        \caption{Multiprogram sets}
        \label{multiprogram}
        \begin{tabular}{c|c|c|c|c|}
            \cline{2-5}
             & \multicolumn{2}{|c|c|}{M1}  & \multicolumn{2}{|c|c|}{M2} \\
            \cline{2-5}
             & E & S & E & S\\
            \hline
            \multicolumn{1}{|c|}{P1} & 1 & 5 & 0.6 & 10\\
            \hline
            \multicolumn{1}{|c|}{P2} & 2 & 7 & 2 & 6 \\
        \end{tabular}
    \end{table}
\end{document}

But it is not working and has many errors. How can I fix that?

Answer 1

Like this:

\documentclass[twoside, a4paper]{article}
\usepackage{array}

\begin{document}
    \begin{table}
        \centering
        \caption{Multiprogram sets}
        \label{multiprogram}
        \begin{tabular}{c|c|c|c|c|}
            \cline{2-5}
    & \multicolumn{2}{c|}{M1}  & \multicolumn{2}{c|}{M2} \\
    \cline{2-5}
    & E & S & E & S\\
    \hline
\multicolumn{1}{|c|}{P1} & 1 & 5 & 0.6 & 10\\
    \hline
\multicolumn{1}{|c|}{P2} & 2 & 7 & 2 & 6 \\
    \hline
        \end{tabular}
    \end{table}
\end{document}

or with equal width of columns, using tabularray packageČ

\documentclass[twoside, a4paper]{article}
\usepackage[skip=1ex]{caption}
\usepackage{tabularray}

\begin{document}
    \begin{table}
    \centering
\caption{Multiprogram sets}
\label{multiprogram}
    \begin{tblr}{hline{1}={2-Z}{solid}, hline{2-Z}=solid, 
                 vline{1}={3-Z}{solid}, vline{2-Z}=solid,
                 colspec= {*{5}{Q[c, wd=3em]}},
                 }
\SetCell[r=2]{c}
    &   \SetCell[c=2]{c}  M1
        &       &   \SetCell[c=2]{c}  M2    
                    &       \\
    & E & S & E     & S     \\
P1  & 1 & 5 & 0.6   & 10    \\
P2  & 2 & 7 & 2     & 6     \\
    \end{tblr}
    \end{table}
\end{document}

Answer 2

If all you wish to achieve is to get the code to compile, simply replace both instances of \multicolumn{2}{|c|c|} with \multicolumn{2}{c|}. This measure has already been suggested by @JensHabricht in a comment and in Zarko's answer.

If, in addition, you would like your table to have better visual appeal, do also consider (a) giving equal widths to the four data columns and (b) aligning the numbers in the final two data columns on their explicit or implict decimal markers. The result of the making these adjustments is shown in the second table, labelled "improved version", in the following screenshot.

\documentclass{article}

%% setup code for second version of table:
\usepackage{siunitx,array,calc}
\newcolumntype{T}[1]{S[table-format=#1]}
\newcommand\mc[1]{\multicolumn{1}{c|}{#1}}
\newcommand\mw[1]{\multicolumn{1}{wc{\widthof{0.6}}|}{#1}}

\begin{document}
    \begin{table}
        \centering
        \caption{Initial version}
        \label{multiprogram}
        \begin{tabular}{c|c|c|c|c|}
            \cline{2-5}
             & \multicolumn{2}{c|}{M1}  & \multicolumn{2}{c|}{M2} \\
            \cline{2-5}
             & E & S & E & S\\
            \hline
            \multicolumn{1}{|c|}{P1} & 1 & 5 & 0.6 & 10\\
            \hline
            \multicolumn{1}{|c|}{P2} & 2 & 7 & 2 & 6 \\
        \end{tabular}        
        
        \bigskip\bigskip
        \setlength\extrarowheight{2pt}
        \caption{Improved version\strut}
        \label{tab:multi}
        \begin{tabular}{| c | c | c | T{1.1}| T{2.0} |}
            \cline{2-5}
            \mc{} & \multicolumn{2}{c|}{M1}  & \multicolumn{2}{c|}{M2} \\
            \cline{2-5}
            \mc{} & \mw{E} & \mw{S} & \mw{E} & \mw{S} \\
            \hline
            P1 & 1 & 5 & 0.6 & 10 \\
            \hline
            P2 & 2 & 7 & 2   & 6  \\
            \hline
        \end{tabular}
    \end{table}
\end{document}