列表中出现未定义的控制序列错误

Question

我尝试在文档中添加 SQL 代码。我使用了以下代码。

\documentclass[12pt]{article}
\usepackage{amsmath, amssymb,amsthm,verbatim}
\usepackage{color}
\usepackage{xcolor}
\usepackage{listings}
\usepackage{textcomp}
\definecolor{codegreen}{rgb}{0,0.6,0}
\definecolor{codegray}{rgb}{0.5,0.5,0.5}
\definecolor{codepurple}{HTML}{C42043}
\definecolor{backcolour}{HTML}{F2F2F2}
\definecolor{bookColor}{cmyk}{0,0,0,0.90}
\color{bookColor}

\lstset{upquote=true}

\lstdefinestyle{mystyle}{
    backgroundcolor=\color{backcolour},
    commentstyle=\color{codegreen},
    keywordstyle=\color{codepurple},
    numberstyle=\numberstyle,
    stringstyle=\color{codepurple},
    basicstyle=\footnotesize\ttfamily,
    breakatwhitespace=false,
    breaklines=true,
    captionpos=b,
    keepspaces=true,
    numbers=left,
    numbersep=10pt,
    showspaces=false,
    showstringspaces=false,
    showtabs=false,
}
\lstset{style=mystyle}



\title{SQL }
\begin{document}
\maketitle

\begin{lstlisting}[ language=SQL,
                    deletekeywords={IDENTITY},
                    deletekeywords={[2]INT},
                    morekeywords={clustered},
                    framesep=8pt,
                    xleftmargin=40pt,
                    framexleftmargin=40pt,
                    frame=tb,
                    framerule=0pt, ]
SELECT
    LOCATION, COUNT(EMP_ID) AS Count_of_Employees
FROM
    DEPARTMENT
        FULL OUTER JOIN
    EMPLOYEE ON DEPARTMENT.DEPT_ID = EMPLOYEE.DEPT_ID
GROUP BY DEPARTMENT.LOCATION
ORDER BY DEPARTMENT.LOCATION
;
\end{lstlisting}
\end{document} 

尽管 PDF 正在生成，但我收到以下错误。

! Undefined control sequence.
\lst@numberstyle -> \numberstyle