<
fixed width in a table >
less than
footnote within table
How to get a footnote in a LaTeX table?
Problem
Because tables are float objects, footnotes could not be used within them.
Solution
Here is also the tabularx package the solution.
Example
\documentclass{article}
\usepackage{tabularx}
\begin{document}
\begin{tabularx}{8cm}{|X|X|X|X|}
\hline
In this table & each column got the same & width & 2cm \\
\hline
As one could & easy see\footnote{really easy to see} & the width is & to small for some of the cells \\
\hline
\end{tabularx}
\end{document}
Output: