Introduction

A question I recently saw on Stack Overflow titled Faster way to delete matching [database] rows? prompted me to organize my thoughts and observations on the subject and quickly jot them down here.

Here is the brief description of the task: say, you have 2 MySQL tables a and b. The tables contain the same type of data, for example log entries. Now you want to delete all or a subset of the entries in table a that exist in table b.

Solutions Suggested By Others

DELETE FROM a WHERE EXISTS (SELECT b.id FROM b WHERE b.id = a.id);

DELETE a FROM a INNER JOIN b on a.id=b.id;

DELETE FROM a WHERE id IN (SELECT id FROM b)

The Problem With Suggested Solutions

Solutions above are all fine if the tables are quite small and the …

Today was at the faculty of Industrial Design in Delft to attend the first 'c,mm,n Garage' event. c,mm,n - pronounced as common - is a project to develop sustainable mobility. It is led by Stichting Natuur en Milieu, The Netherlands Society for Nature and Environment and currently the main participants are students from a number of Dutch technical universities.

Right now, engineering efforts are focused on a clean, remanufacturable car that runs on electricity generated by a hydrogen fuel cell:
The car is almost completely built out of biodegradable plastics, making it extremely light and environmentally friendly.
There is a YouTube Video available that shows off the exterior design and which gives you a good impression of how open and …