\documentclass[margin=5mm]{standalone}
%%%<
\usepackage{verbatim}
% Example data
\usepackage{filecontents}
\begin{filecontents*}{data.csv}
  Number   Orders   Day
  1   816   June\ 19
  2   687   June\ 20
  3   676   June\ 21
  4   597   June\ 22
  5   743   June\ 25
  6   718   June\ 26
  7   702   June\ 27
  8   634   June\ 28
  9   581   June\ 29
  10   743   July\ 2
  11   731   July\ 3
  12   736   July\ 4
  13   691   July\ 5
  14   626   July\ 6
  15   788   July\ 9
  16   667   July\ 10
  17   737   July\ 11
  18   678   July\ 12
  19   560   July\ 13
\end{filecontents*}
%%%>
\begin{comment}
:Title: Group plot
:Tags: 2D;Group plots;PGFPlotstable
:Author: Elke Schubert
:Slug: group-plot

A group plot example.
\end{comment}
\usepackage{pgfplots}
\pgfplotsset{compat=1.8}
\usepackage{pgfplotstable}
\usepgfplotslibrary{groupplots}
\begin{document}
\begin{tikzpicture}
  % Read the file
  % if needed, define column separators by pgfplotstableread[col sep=...]{}{}
 \pgfplotstableread{data.csv}{\Data}
 \begin{groupplot}[
     group style = {group size = 2 by 1},
     height = 10cm,
     width = 10cm,
     ymin = 500,
     xticklabels from table = {\Data}{Day}, xtick = {1,...,19},
     xticklabel style = {rotate = 90, xshift = -0.8ex, anchor = mid east}
    ]
    \nextgroupplot[xmin = 1, xmax = 19, ymax = 900]
      \addplot[very thick] table [x = Number, y = Orders] {\Data};
      \draw[red, dashed, thick] (axis cs:11,0) rectangle (axis cs:32,850);
    \nextgroupplot[xmin = 11, xmax = 19, ymax = 850, width = 5cm]
      \addplot[very thick] table [x = Number, y = Orders] {\Data};
  \end{groupplot}
  \draw[thick, blue, ->, shorten >=2pt, shorten <=2pt] (group c1r1.east)
  -- (group c2r1.west);
\end{tikzpicture}
\end{document}