How to fix the width of longtable LATEX - latex

Question

I want to set the width of my longtable so it fits within the page and not crops out. I have 206 columns and 17 rows.
I use tablesgenerator.com to get my longtable, but the option "Scale table to text width" doesn't work with longtable, could use some help. (Latex beginner here).
\documentclass{article}
\usepackage{longtable}
\usepackage{booktabs}
\begin{document}
\begin{longtable}{#{}lllllllllllllllll#{}}
\toprule
\textbf{SN} & \textbf{zhelio} & \textbf{zhelio\_un} & \textbf{zCMB} &
\textbf{zCMB\_un} & \textbf{Peak\_MJD} & \textbf{Peak\_MJD\_un} & \textbf{x1}
& \textbf{x1\_un} & \textbf{c} & \textbf{c\_un} & \textbf{mB} &
\textbf{mB\_un} & \textbf{t} & \textbf{t\_un} & \textbf{Host\_logmass} &
\textbf{Host\_logmass\_un} \\* \midrule
\endhead
%table stuff here...
\caption{}
\label{tab:my-table}\\
\end{longtable}
\end{document}
This is what it looks like

Answer 1

Assuming you mean 206 rows and not columns, then you could try the following strategies:
put the table on landscape pages
use a smaller font
reduce the margins of your document to have more space
reduce the space between columns
\documentclass{article}
\usepackage{longtable}
\usepackage{booktabs}
\usepackage[vmargin=2cm]{geometry}
\usepackage{lscape}
\begin{document}
\begin{landscape}
\small
\setlength{\tabcolsep}{2pt}
\begin{longtable}{#{}lllllllllllllllll#{}}
\toprule
\textbf{SN} & \textbf{zhelio} & \textbf{zhelio\_un} & \textbf{zCMB} &
\textbf{zCMB\_un} & \textbf{Peak\_MJD} & \textbf{Peak\_MJD\_un} & \textbf{x1}
& \textbf{x1\_un} & \textbf{c} & \textbf{c\_un} & \textbf{mB} &
\textbf{mB\_un} & \textbf{t} & \textbf{t\_un} & \textbf{Host\_logmass} &
\textbf{Host\_logmass\_un} \\* \midrule
\endhead
%table stuff here...
\caption{}
\label{tab:my-table}\\
\end{longtable}
\end{landscape}
\end{document}