Dynamic row height adjustment in tables with multirow

Question

I need to create a table in LaTeX that looks exactly like its counterpart in a Word document.

For this, I need a table that can span multiple pages with repeating headers (longtable, etc.) and contains merged cells with horizontally and vertically centered content (multirow, makecell, etc.). Some of the content needs to be rotated/vertical.

Currently, I'm struggling with overflowing content in a multirow environment. I have tried to find a solution for over a day now:

\documentclass{article}

\usepackage{xltabular}
\usepackage{array}
\usepackage{makecell}
\usepackage{multirow}
\usepackage{graphicx}

\begin{document}
  \begin{xltabular}{\textwidth}{|X|X|}  
    \hline
    \thead{Two \\ lines} & \thead{One vertically centered line} \\
    \hline
    \multirowcell{2}{\rotatebox{90}{LONG CENTERED STRING }} & \makecell{Something} \\
    \cline{2-2}
    & \makecell{Something} \\            
    \hline
  \end{xltabular}
\end{document}

How can I make the table adjust all the row heights based on the highest row? That is, how can I make the table adjust the height of the two "Something" rows so that they're equal in height to the "LONG CENTERED STRING" multirow cell?

(I'd prefer a non-cheating, dynamic solution as the content of the table is also somewhat dynamically generated. Hence, adjusting row heights manually or inserting fake rows is not ideal.)

Answer 1

Here is a fully automatic version. No guessing about the number of rows. It measures the length of the vertical text and uses that to put struts in the second column cells. I have no idea if this can be generalised to your use case, however.

\documentclass{article}
\usepackage{rotating}
\usepackage{xltabular}
\usepackage{booktabs}
\usepackage{makecell}
\usepackage{multirow}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\begin{document}

\newcommand{\verticaltext}{ LONG CENTERED STRING }
\newlength{\verticalsize}
\settowidth{\verticalsize}{\verticaltext}
\newcommand{\halfstrut}{\rule[-0.25\verticalsize]{0pt}{0.5\verticalsize}}

\begin{xltabular}{.7\textwidth}{CC}\toprule
\thead{Two \\ lines} & \thead{One vertically centered line} \\\midrule
\multirow[c]{1}*[20pt]{\begin{turn}{90} \verticaltext \end{turn}}
                     & \halfstrut a \\ \cmidrule{2-2}
                     & \halfstrut b \\ \midrule
whatever \\\bottomrule
\end{xltabular}

\end{document}

Answer 2

My approach, already suggested by Zarko, would be take care of the number of rows used by the rotated cell and the cells at the right:

\documentclass{article}
\usepackage{rotating}
\usepackage{xltabular}
\usepackage{booktabs}
\usepackage{makecell}
\usepackage{multirow}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\begin{document}
\begin{xltabular}{.7\textwidth}{CC}\toprule
\thead{Two \\ lines} & \thead{One vertically centered line} \\\midrule
\multirow{12.5}{*}{\begin{turn}{90} LONG CENTERED STRING \end{turn}} 
& \multirow{7}{*}{a}\\\\\\\\\\\\\cmidrule{2-2}
& \multirow{7}{*}{b}\\\\\\\\\\\\\midrule
whatever
\\\bottomrule
\end{xltabular}