Basis of selection I
In this module we will learn how to write our first SQL queries, deal with such important concepts as conditional selection, sorting and data grouping.
Basis of selection II
We continue to write increasingly complex select queries: we learn how to get data from several tables, write subqueries, and get acquainted with a common table expression.
In the previous modules, we learned how to write select-only queries, it's time to fool around more seriously: we get acquainted with adding, updating, and deleting records.