\textbf{47.Consider the following relations:\\
\includegraphics[width=120mm]{Image6.png}\\
Consider the following SQL query.\\
SELECT S.Student$_$Name, sum (P.Marks)\\
FROM Student S,Performance P\\
WHERE S.Roll$_$No=P.Roll$_$No \\
GROUP BY S.Student$_$Name\\
The number of rows that will be returned by the SQL query is .........}\\
\vspace{2mm}\\
错误缺少{插入....请帮帮我！
答案1
_在数学模式中，要求将参数放入下标位置。使用\_或\textunderscore代替$_$：
SELECT S.Student\_Name
或者逐字使用：
\verb|S.Student_Name|
或listings代码清单包
或者 ...
扫描时文件结束使用\textbf
}行中缺少结尾\textbf。更正：
\textbf{47.Consider the following relations:}\\