> ‘processing’ means any operation or set of operations which is performed on personal data or on sets of personal data, whether or not by automated means, such as collection, recording, organisation, structuring, storage, adaptation or alteration, retrieval, consultation, use, disclosure by transmission, dissemination or otherwise making available, alignment or combination, restriction, erasure or destruction;

So not a database query itself, but the thing that drives the database query. It also extends to things like logs - aka don't keep a log full of SQL queries that are full of peoples personal information. Don't ship that log off to some third party, or make it available to random people.

For web apps it's mostly the storage and retrieval aspects that are important. Don't store too much PII. Don't allow anybody to access it at the DB level. Implement appropriate access restrictions at the web-app level.