\begin{frame} \frametitle{Joins} Up to version SQL-86, there were no explicit joins in queries. Instead, Cartesian products of relations filtered via \sql{where}. \bigskip \begin{code}{\textwidth}{} \small \BUseVerbatim{query} \end{code} \pause\smallskip \begin{goal}{} Since SQL-92 there are explicit join operations. \end{goal} \end{frame}