Three techniques for sum types in SQL (absorption, separation, and partition): https://www.parsonsmatt.org/2019/03/19/sum_types_in_sql.html https://www.parsons

Three techniques for sum types in SQL (absorption, separation, and partition): https://www.parsonsmatt.org/2019/03/19/sum_types_in_sql.html https://www.parsonsmatt.org/2019/03/19/sum_types_in_sql.html Also, here is a relational database system with native support for sum types (and also no "NULL" nonsense, which is also not part of pure relational algebra): https://github.com/agentm/project-m36 https://github.com/agentm/project-m36