Sorting in Pgfplotstable not working

Question

I am trying to sort a table I created with the pgfplotstable package and I can't find out why it is not working.

\pgfplotstableset{col sep=semicolon, use comma, fixed, set thousands separator={}}
\pgfplotstableread
{
Matrikelnummer;Note     
1010123;1.4
1010121;2.3
1010122;1.1
}\loadedtable

\pgfplotstabletypeset[sort, sort key={Matrikelnummer}]\loadedtable

When I change the sort key to "Note" it works like a charm. But the example above simply does not change the order.

Answer 1

If you set sort cmp={int <} it works fine.

\documentclass{article}
\usepackage{pgfplotstable}
\begin{document}
\pgfplotstableset{col sep=semicolon, use comma, fixed, set thousands separator={}}
\pgfplotstableread
{
Matrikelnummer;Note     
1010123;1.4
1010121;2.3
1010122;1.1
}\loadedtable

\pgfplotstabletypeset[sort,sort cmp={int <},sort key=Matrikelnummer]\loadedtable

\end{document}