How can I make queries secret? I have a project whose activity I need to keep private, and I'm not the server administrator.
If my app updates a value for the user with id 1, it would probably say something like UPDATE 'users' SET 'Name' = 'George' WHERE 'Id' = 1; and that will show in the Apache log.
What can I do to avoid this?
The Apache logs show what the Apache Web Server has been asked to do.
It generally knows (nor cares) not a jot about SQL.  Of any flavour.
Please, please, please tell me you're not submitting raw SQL statements to your web application through the URL and/or QueryString and executing them!
Obligatory XKCD Reference: Little Bobby Tables.
This is a huge Security Risk and, if Apache really is logging queries, including Personal Data into its own, largely unsecured, log file then you're heading into very dangerous waters with regards to Data Protection legislation (e.g. GDPR).