数据集的箱线图，其中元数据在一列，数据在另一列

Question

我如何指示pgfplots从一列中有标识符（Label在下面的示例中）且另一列中有数据（Value在下面的示例中）的数据集生成箱线图？我希望该图与第一个图相似，但不必为每个值手动创建单独的数据集Label。

示例数据：

\documentclass{article}

\usepackage{pgfplots}
\pgfplotsset{compat=newest}
\usepgfplotslibrary{statistics}

\usepackage{pgfplotstable}

\pgfplotstableset{%
    columns/Label/.style={string type},
}
\pgfplotstablenew[%
        create on use/Label/.style={create col/set={A}},
        create on use/Value/.style={create col/expr={rand}},
        columns={Label,Value}
]{10}\Asamples
\pgfplotstablenew[%
        create on use/Label/.style={create col/set={B}},
        create on use/Value/.style={create col/expr={rand}},
        columns={Label,Value}
]{10}\Bsamples
\pgfplotstablenew[%
    create on use/Label/.style={copy column from table={\Asamples}{Label}},
    create on use/Value/.style={copy column from table={\Asamples}{Value}},
    columns={Label,Value}
]{10}\ABsamples
\pgfplotstablevertcat{\ABsamples}{\Bsamples}%

\begin{document}

% Works fine
\begin{tikzpicture}
    \begin{axis}[
        ytick={1,2},
        yticklabels={Group A, Group B},
    ]
        \addplot[boxplot] table[y=Value] \Asamples;
        \addplot[boxplot] table[y=Value] \Bsamples;
    \end{axis}
\end{tikzpicture}

% Does not work as intended
% The plot should be similar to the above 
% with one box for A and one for B
\begin{tikzpicture}
    \begin{axis}[
        ytick={1,2},
        yticklabels={Group A, Group B},
    ]
        \addplot[boxplot] table[x=Label,y=Value] \ABsamples;
    \end{axis}
\end{tikzpicture}

\end{document}