Centering lstlisting environment

Question

I'd like to center (horizontally) the lstlisting environment in the page. I tried using "xleftmargin=0.2\textwidth" but the result is not that satisfying. I tried to include the lstlisting env in a center env (parent-child), but it doesn't work. I even tried including lstlisting in a figure env, then \centering and then the lstlising, but this didn't work too.

I looked at several posts, especially this one, but the given solution is not actually working for me. I'll leave the code I wrote down.

\documentclass{article}
\usepackage{listings}
\begin{document}
   \lstset{frame=none,
    language=SQL,
    aboveskip=3mm,
    belowskip=3mm,
    showstringspaces=false,
    columns=flexible,
    basicstyle={\ttfamily},
    numbers=none,
    numberstyle=\tiny\color{gray},
    keywordstyle=\bfseries,
    commentstyle=\color{dkgreen},
    stringstyle=\color{mauve},
    tabsize=4,
    captionpos=b
   }

   \begin{lstlisting}
       create table Student
       (
           Number       char(16) primary key,
           Name         varchar(30),
           Surname      varchar(30)
    )
    \end{lstlisting}
\end{document}

I also noticed that without specifying any "tabsize" value, it gets centered automatically, but I really need that value for tabsize.

Answer 1

The solution from linked question works and I don't see differences with or without tabsize=4. Note the added option gobble.

\documentclass{article}
\usepackage[pass, showframe]{geometry} % show centering effect
\usepackage{listings}
\usepackage{fancybox}

\makeatletter
\newenvironment{CenteredBox}{% 
  \begin{Sbox}%
}{% Save the content in a box
  \end{Sbox}\centerline{\parbox{\wd\@Sbox}{\TheSbox}}%
}% And output it centered
\makeatother

\begin{document}
   \lstset{frame=none,
    language=SQL,
    aboveskip=3mm,
    belowskip=3mm,
    showstringspaces=false,
    columns=flexible,
    basicstyle={\ttfamily},
    numbers=none,
    numberstyle=\tiny\color{gray},
    keywordstyle=\bfseries,
    commentstyle=\color{dkgreen},
    stringstyle=\color{mauve},
    tabsize=4,
    captionpos=b
   }

\begin{CenteredBox}
   % "gobble" IS required
   \begin{lstlisting}[gobble=7]
       create table Student
       (
           Number       char(16) primary key,
           Name         varchar(30),
           Surname      varchar(30)
       )
    \end{lstlisting}
\end{CenteredBox}
\end{document}