LaTeX/Packages/Listings and subindex

Question

I am using LaTeX/Packages/Listings AND this code to make a rectangle with sql source code inside of it, but I would like to have the option to insert subindexes...

I try it using the following but had no success, any idea?

\lstset{language=SQL, caption=SQL, label=SQL, frame=shadowbox, rulesepcolor=\color{blue}}
\begin{lstlisting}
       SELECT  SUM($x_{1}$ *$x_{1}$ FROM X;
\end{lstlisting}

I would like to make the $x_1$ shows right

Answer 1

You need to add mathescape=true. Here is the output without and with this added:

\documentclass[border=2pt]{standalone}
\usepackage{xcolor}
\usepackage{listings}

\begin{document}
\lstset{language=SQL, caption=SQL, label=SQL, frame=shadowbox, rulesepcolor=\color{blue}}
\begin{lstlisting}
       SELECT  SUM($x_{1}$ *$x_{1}$ FROM X;
\end{lstlisting}

\begin{lstlisting}[mathescape=true]
       SELECT  SUM($x_{1}$ *$x_{1}$ FROM X;
\end{lstlisting}
\end{document}