Comment by Beanis

Postgres bulk update:

http://sqlfiddle.com/#!17/b3d19/1

You can do something similar in MySQL with temp tables.

Bulk update through upsert (slightly different than a bulk update, since it can create rows too)

MySQL: http://sqlfiddle.com/#!9/a6f050/1

Postgres: http://sqlfiddle.com/#!17/a8367/1