jeudi 31 janvier 2019

Support for LATERAL derived tables added to MySQL 8.0.14

Hello all. Last months have been busy for me with various tasks, and one of them is finally done and released in MySQL 8.0.14 : LATERAL derived tables. All details are in my post on mysqlserverteam. I think it is a useful addition to our SQL capabilities. Enjoy!

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 😊.

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 😃 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...

jeudi 22 septembre 2016

MySQL 8.0 Labs: [Recursive] Common Table Expressions in MySQL (CTEs)

I realize that these last months I have not published anything... it's because I was quite busy developing a prominent feature: [Recursive] Common Table Expressions, also known as
  • [recursive] CTE,
  • [recursive] subquery factoring,
  • WITH [RECURSIVE] clause.
This feature is available today, in a Labs release of the MySQL Server.
In my post here, you will find more information: syntax, capacities, examples...
Feels good to have this big piece of work finally out!