\begin{frame} \frametitle{Subqueries under From} Since an \emph{SQL query returns a table}, it makes sense to use a subquery wherever a table might be specified. \begin{goal}{} SQL allows subqueries in the \sql{from} clause. \end{goal} \pause\bigskip \begin{code}{\textwidth}{Points (in\ \%) achieved in homework exercise 1} \footnotesize \BUseVerbatim{query} \end{code} Note: join of \sql{Results} and \sql{Exercises} is computed in a subquery. \pause\vspace{0ex} \begin{goal}{} One use of subqueries under \sql{from} are \emph{nested aggregations}. \end{goal} \end{frame}