Hi, I understand you are concerned about your PHP code's security against SQL injection. I can look at your code, find any unprotected inputs and variables where someone could inject SQL code, and fix the issues. Most of the time it's a matter of not querying the database directly.
I'm a web developer with years of experience and I've worked on countless websites and PHP / Javascript / SQL web apps always according to security standards.
Feel free to send me your code or ask any questions!