Simple table with caption:

\begin{longtable}[]{@{}rlcl@{}}
\caption{Demonstration of simple table syntax.}\tabularnewline
\toprule()
Right & Left & Center & Default \\
\midrule()
\endfirsthead
\toprule()
Right & Left & Center & Default \\
\midrule()
\endhead
12 & 12 & 12 & 12 \\
123 & 123 & 123 & 123 \\
1 & 1 & 1 & 1 \\
\bottomrule()
\end{longtable}

Simple table without caption:

\begin{longtable}[]{@{}rlcl@{}}
\toprule()
Right & Left & Center & Default \\
\midrule()
\endhead
12 & 12 & 12 & 12 \\
123 & 123 & 123 & 123 \\
1 & 1 & 1 & 1 \\
\bottomrule()
\end{longtable}

Simple table indented two spaces:

\begin{longtable}[]{@{}rlcl@{}}
\caption{Demonstration of simple table syntax.}\tabularnewline
\toprule()
Right & Left & Center & Default \\
\midrule()
\endfirsthead
\toprule()
Right & Left & Center & Default \\
\midrule()
\endhead
12 & 12 & 12 & 12 \\
123 & 123 & 123 & 123 \\
1 & 1 & 1 & 1 \\
\bottomrule()
\end{longtable}

Multiline table with caption:

\begin{longtable}[]{@{}
  >{\centering\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1500}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1375}}
  >{\raggedleft\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1625}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.3500}}@{}}
\caption{Here's the caption. It may span multiple lines.}\tabularnewline
\toprule()
\begin{minipage}[b]{\linewidth}\centering
Centered Header
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedright
Left Aligned
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedleft
Right Aligned
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedright
Default aligned
\end{minipage} \\
\midrule()
\endfirsthead
\toprule()
\begin{minipage}[b]{\linewidth}\centering
Centered Header
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedright
Left Aligned
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedleft
Right Aligned
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedright
Default aligned
\end{minipage} \\
\midrule()
\endhead
First & row & 12.0 & Example of a row that spans multiple lines. \\
Second & row & 5.0 & Here's another one. Note the blank line between rows. \\
\bottomrule()
\end{longtable}

Multiline table without caption:

\begin{longtable}[]{@{}
  >{\centering\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1500}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1375}}
  >{\raggedleft\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1625}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.3500}}@{}}
\toprule()
\begin{minipage}[b]{\linewidth}\centering
Centered Header
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedright
Left Aligned
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedleft
Right Aligned
\end{minipage} & \begin{minipage}[b]{\linewidth}\raggedright
Default aligned
\end{minipage} \\
\midrule()
\endhead
First & row & 12.0 & Example of a row that spans multiple lines. \\
Second & row & 5.0 & Here's another one. Note the blank line between rows. \\
\bottomrule()
\end{longtable}

Table without column headers:

\begin{longtable}[]{@{}rlcr@{}}
\toprule()
\endhead
12 & 12 & 12 & 12 \\
123 & 123 & 123 & 123 \\
1 & 1 & 1 & 1 \\
\bottomrule()
\end{longtable}

Multiline table without column headers:

\begin{longtable}[]{@{}
  >{\centering\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1500}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1375}}
  >{\raggedleft\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.1625}}
  >{\raggedright\arraybackslash}p{(\columnwidth - 6\tabcolsep) * \real{0.3500}}@{}}
\toprule()
\endhead
First & row & 12.0 & Example of a row that spans multiple lines. \\
Second & row & 5.0 & Here's another one. Note the blank line between rows. \\
\bottomrule()
\end{longtable}