I had a look at a few similar questions but none seems to be identical to mine.
Here is a MWE:
\documentclass[a4paper]{article}
\usepackage{multirow}
\usepackage{multicol}
\begin{document}
\begin{tabular}{|*{5}{c|}}
\hline
\backslashbox{1}{2} & A & B & C & D \\
\hline
a & \multicolumn{3}{c|}{\multirow{3}{*}{P}} & x \\
\cline{1-1} \cline{5-5}
b & & & & y \\
\cline{1-1} \cline{5-5}
c & & & & z \\
\hline
d & q & n & t & r \\
\hline
e & l & m & s & p \\
\hline
\end{tabular}
\end{document}
The column B is partially bounded by 2 vertical lines. I would prefer to have a big 3 by 3 cell for the entry P.
How can I do that?
Just add "phantom" multicolumns below the cell containing P:
\documentclass[a4paper]{article}
\usepackage{multirow}
\usepackage{multicol}
\begin{document}
\begin{tabular}{|*{5}{c|}}
\hline
\backslashbox{1}{2} & A & B & C & D \\
\hline
a & \multicolumn{3}{c|}{\multirow{3}{*}{P}} & x \\
\cline{1-1} \cline{5-5}
%% Add a \multicolumn here
b & \multicolumn{3}{c|}{} & x \\
\cline{1-1} \cline{5-5}
%% Add a \multicolumn here
c & \multicolumn{3}{c|}{}& z \\
\hline
d & q & n & t & r \\
\hline
e & l & m & s & p \\
\hline
\end{tabular}
\end{document}