# Yet another issue on spanning columns

There are a lot of examples on spanning columns and rows in a table. I tried them to create a table like this but failed!

           +-----------------------------+
| A  |  B |  C |  D | E  | F  |
+----+----+-----------------------------+
| 1  | 2  | 30 | 40 | 50 | 60 | 70 | 80 |
|    | 3  | 31 | 41 | 51 | 61 | 71 | 81 |
+----+----+-----------------------------+
| 4  | 5  | 32 | 42 | 52 | 62 | 72 | 82 |
|    | 6  | 33 | 43 | 53 | 63 | 73 | 83 |
+----+----+-----------------------------+


Here is the code I wrote

\begin{table*}
\centering
\caption{Prefetchers coverage}
\label{prefetch-coverage}
\begin{tabular}{ |c|c|c|c|c|c|c|c|}
\cline{3-8}
\\multicolumn{2}{c}{}      &       &   A   &   B   &   C   &    D   &   E   &   F \\
\hline
1  &   2   &  30   &  40   &  50   &  60    &  70   &  80   \\
\cline{2-8}
&   3   &  31   &  41   &  51   &  61    & 71    &  81   \\
\hline
4  &   5   &  32   &  42   &  52   &  62    & 72    &  82   \\
\cline{2-8}
&   6   &  33   &  43   &  53   &  63    & 73    &  83   \\
\hline
\end{tabular}
\end{table*}


The output however is fragmented in the first row. Where did I miss?

You have \\multicolumn which is wrong. Then you should have

\multicolumn{2}{c|}{}


in order to print the rule.

Here's the correct code, with also a different way to lay out your table.

\documentclass[twocolumn]{article}
\usepackage{booktabs} % for the second table

\begin{document}
\begin{table*}
\centering
\caption{Prefetchers coverage}
\label{prefetch-coverage}

\medskip

\begin{tabular}{|*{8}{c|}}
\cline{3-8}
\multicolumn{2}{c|}{}     &  A &  B &  C &  D &  E &  F \\
\hline
1 & 2 & 30 & 40 & 50 & 60 & 70 & 80 \\
\cline{2-8}
& 3 & 31 & 41 & 51 & 61 & 71 & 81 \\
\hline
4 & 5 & 32 & 42 & 52 & 62 & 72 & 82 \\
\cline{2-8}
& 6 & 33 & 43 & 53 & 63 & 73 & 83 \\
\hline
\end{tabular}
\end{table*}
\begin{table*}
\centering
\caption{Prefetchers coverage}
\label{prefetch-coverage2}

\medskip

\begin{tabular}{*{8}{c}}
\toprule
&   &  A &  B &  C &  D &  E &  F \\
\midrule
1 & 2 & 30 & 40 & 50 & 60 & 70 & 80 \\
& 3 & 31 & 41 & 51 & 61 & 71 & 81 \\
\midrule
4 & 5 & 32 & 42 & 52 & 62 & 72 & 82 \\
& 6 & 33 & 43 & 53 & 63 & 73 & 83 \\
\bottomrule
\end{tabular}
\end{table*}
\end{document}