Merging cells in LaTeX tables

Question

I have a very simple table:

\begin{table}[t]
\begin{tabular}{|c||c|c|c|}
\hline
\multirow{2}{*}{Implementation}         & Test 1  & Test2  &  Test3    \\\hline
                                        & \multicolumn{3}{|c|}{results}   \\\hline\hline
\end{tabular}
\end{table}

It works almost "perfect", the only problem that I have is that the hline still goes through the first two cells that I have merged. Basically, it looks like this

"-------------------------------------------------"
"|                | Test 1 | Test 2 | Test 3 |"
" ----Implementation-------------------------------"
"|                |     results      |"  
"-------------------------------------------------"

However, it should like this:

"-------------------------------------------------" 
"|               | Test 1 | Test 2 | Test 3 |"
"   Implementation    ---------------------------"
"|               |      results     |"   
"-------------------------------------------------"

Anyone an idea how to get rid of the line in the first column?

Thanks

Answer 1

The command you want is \cline{i-j} which lets you draw a row divider across only certain columns. See http://www.giss.nasa.gov/tools/latex/ltx-214.html for details.

In particular, you'll want to use \cline{2-4} to draw a horizontal line across just the columns you mentioned. Here's your code with the one change:

\begin{table}[t]
\begin{tabular}{|c||c|c|c|}
\hline
\multirow{2}{*}{Implementation}         & Test 1  & Test2  &  Test3    \\\cline{2-4}
                                        & \multicolumn{3}{|c|}{results}   \\\hline\hline
\end{tabular}
\end{table}