Hi Nick,

this is what is output to the *gnupolt* buffer:
data = "c:/Users/harald/AppData/Local/Temp/babel-89088ig/gnuplot-8908HEH"
set term svg
set output "data-missing.svg"
set 34
set 56
set 44

this is what I have in the file above:
JET    2012-01-01    1000   
    2012-02-01    2000    100
DUMMY    2012-03-01    3000   
    2012-04-01    4000    100
OMV    2012-05-01    5000   
"OMV PETROM"    2012-06-01    6000   
"OMV PETROM"    2012-07-01    7000   
OMV    2012-08-01    8000   
BP    2012-09-01    9000   

Is this different from what you got?

Thanks & Regards,
Harald

From: Nick Dokos <ndokos <at> gmail.com>
Subject: Re: Bug: missing header argument does not work any longer [8.3.4 (8.3.4-47-gaf853d-elpaplus <at> c:/Users/harald/AppData/Roaming/.emacs.d/elpa/org-plus-contrib-20160502/)]
Newsgroups: gmane.emacs.orgmode
Date: 2016-05-06 18:37:52 GMT (4 days, 1 hour and 53 minutes ago)
Harald Sanftmann <haraldsa <at> web.de> writes:

> I have some org-tables which contain empty fields. I specified :missing "?" to get the right results.
> When I try to plot them with Gnuplot the empty fields are not exported as '?' but just as empty strings
> ''. Gnuplot therefore just uses the next non empty field for the value and therefore shifts the columns
> of the given row.
>
> To make it more concrete:
>
>   #+TBLNAME: data-missing
>   | Comment    |    gnutime | milage/km | something else |
>   |------------+------------+-----------+----------------|
>   | JET        | 2012-01-01 |      1000 |                |
>   |            | 2012-02-01 |      2000 |            100 |
>   | DUMMY      | 2012-03-01 |      3000 |                |
>   |            | 2012-04-01 |      4000 |            100 |
>   | OMV        | 2012-05-01 |      5000 |                |
>   | OMV PETROM | 2012-06-01 |      6000 |                |
>   | OMV PETROM | 2012-07-01 |      7000 |                |
>   | OMV        | 2012-08-01 |      8000 |                |
>   | BP         | 2012-09-01 |      9000 |                |
>   #+begin_src gnuplot :var data=data-missing :exports both :file data-missing.svg :missing "?" :set
> "xtics nomirror rotate by -45 font \",8\""
>   reset
>   set xtics nomirror rotate by -45 font ",8"
>   set title "Fahr Plot"
>   set xdata time
>   set timefmt "%Y-%m-%d-%H:%M:%S"
>   set xlabel "Time"
>   set ylabel "Distance"
>   set format y "%.0s T%cm"
>   set key top left
>   FIT_LIMIT = 1e-36
>   m=100
>   c=-100000
>  
>   y(x) = m*x+c
>   fit y(x) data using 2:3 via c, m
>  
>   plot data u 2:3 w lp lw 1 title 'Distance', \
>        y(x) title "line fit"
>   #+end_src
>
> This is what I get:
> [cid]   
>
> When I fill out the empty fields in the first column of the table I get the right result:
> [cid]   
> I am using Org-mode version 8.3.4. With Org Version 8.2.5h everything works fine.
>
>
> Emacs  : GNU Emacs 24.5.1 (i686-pc-mingw32)
>  of 2015-04-11 on LEG570
> Package: Org-mode version 8.3.4 (8.3.4-47-gaf853d-elpaplus  <at>  c:/Users/harald/AppData/Roaming/.emacs.d/
> elpa/org-plus-contrib-20160502/)

I use more-or-less latest org:

Org-mode version 8.3.4 (release_8.3.4-718-g634e12)
GNU Emacs 25.0.50.4 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9)

FWIW, I cannot reproduce this problem: the plot comes out fine.

--
Nick