Relational databases are designed to operate efficiently with set-based queries; they do not perform as well with loops and cursors. However, there are situations where you need a loop of some fashion. Tally tables give you the best of both worlds by allowing you to effectively “loop” through records in a set-based manner. We’ll explore what tally tables are, how they work, and, more importantly, review some of the many ways you can use them to turn your loops and cursors into efficient set-based operations.