You are making the last column of your table as a SI (S
) column, so you must wrap non-number contents in that column inside braces. Btw h!!
is nonsense.
\documentclass[a4paper]{article}
\usepackage{amsmath, amsthm, amssymb, mathtools}
\usepackage{siunitx}
\begin{document}
\begin{table}[h!]
\small
\renewcommand{\arraystretch}{1.2}
\setlength\tabcolsep{3pt}
\begin{tabular*}{\linewidth}{l@{\extracolsep{\fill}}c c c S[table-format=3.1]c}
De & V (km) & S (\si{\degree}) & P (min) &{Per (dny)}\\
\hline
A & 840 & 98,7 & 101.5 & 0,07048\\
B & 785 & 98,7 & 101.4 & 0,07041\\
C & 775-790 & 98,6 & 100.4 & 0,06972\\
D & 612-640 & 98,0 & 97.1 & 0,06743
\end{tabular*}
\end{table}
\end{document}
However it will change the commas to dots in the last column. To avoid this, read this question.
It seems to me that you are trying to make the second last column to be a SI column, so you should place S[table-format=3.1]
somewhere else. My final answer:
\documentclass[a4paper]{article}
\usepackage{amsmath, amsthm, amssymb, mathtools}
\usepackage[locale=FR]{siunitx}
\begin{document}
\begin{table}[h!]
\small
\renewcommand{\arraystretch}{1.2}
\setlength\tabcolsep{3pt}
\begin{tabular*}{\linewidth}{l@{\extracolsep{\fill}}c c S[table-format=3.1]c c}
De & V (km) & S (\si{\degree}) & {P (min)} & Per (dny)\\
\hline
A & 840 & 98,7 & 101,5 & 0,07048\\
B & 785 & 98,7 & 101,4 & 0,07041\\
C & 775-790 & 98,6 & 100,4 & 0,06972\\
D & 612-640 & 98,0 & 97,1 & 0,06743
\end{tabular*}
\end{table}
\end{document}

However, take care of the last column. I intentionally keep it, but you may want to reduce its size.
Per (dny)
, if you replace it by\multicolumn{1}{r}{Per (dny)}
there is no error. The reason is that you cannot use such stuff in anS
column. – user121799 Apr 20 '19 at 2:57{Per (dny)}
. – user156344 Apr 20 '19 at 2:57