lundi 27 novembre 2017

Sudoku Recursive Common Table Expression Solver

Colin, from Percona, wrote a nice post demonstrating a funny use of common table expressions: solving a Sudoku Puzzle. Ok, that's not the type of problem which matters a lot to database users... but it still feels good when he mentions that MySQL's implementation (which I wrote), is the fastest of all three tested DBMSs ūüėä.

lundi 2 octobre 2017

Presentation at PerconaLive in Dublin, 25-27 Sep 2017

Back from the PerconaLive conference! It was nice meeting some old faces ūüėÉ There I presented MySQL's Common Table Expressions; check out my slides, with example queries and some details about the implementation. I got two suggestions from the audience:
  1. add to views the same single-materialization which we have in CTEs now (slides 19-27)
  2. support outer references in derived tables and CTEs.
The first point would speed up queries which reference a view more than once. The second point would make it easier to write certain queries, where a subquery depends on the outer query's current row and this subquery contains a CTE. Will I get to work on any of these? Time will tell...