Q:

Database updating wrong data

I am currently working on a fun project, which involves Ajax, HTML, JavaScript, PHP and SQL.
I have debugged my project as far as I could, and I am 100% sure my AJAX, HTML and JavaScript are working fine and my variables are send to the server correctly.
I am trying to fetch data from the database, subtract a number (submitted in the form) from this data and update the database accordingly.
My database does update. However, it is not displaying the correct numbers. When submitting 1 in the form, it will ALWAYS return the same numbers in the database. (Which is odd, because I am subtracting it...). I am 100% sure the data from the form is passed to the server correctly, so I would like you all to check my server file, which should be the problem.
Edit:
The database connection is made in db.php and is made correctly. This has been tested.

A:

You really need to switch to prepared statements to fix your sql injection problems.
Apart from that, what's wrong with this specific code, is that mysql_query does not return a number, it returns a resource. You need to fetch a row to get the number.

