WG211/M20Kameyama

Cheney et al.'s framework for Language-integrated Query performs program transformation and code generation to obtain a single SQL query from an arbitrary query in the source language. An interesting open problem is to extend their framework to grouping and aggregation, which seems impossible to solve if we don't allow subqueries (nested control structures) in SQL. We show that, if we allow subqueries in the target SQL (such as PostgreSQL), the problem can be solved -- nested data structures can be eliminated. (Joint work with Rui Ohkura)