Data prevention using SQL injection

I am looking for an experienced freelancer to help protect the user accounts on our platform from malicious SQL injection attacks. The user accounts are of paramount importance, so we need to make sure their data is secure, which is why we need a secure access system in place. To that end, the security measures to be put in place will be focused on preventing SQL injection attack attempts. This will include measures such as ensuring that all user input is sanitized and that any code running in our environment is thoroughly reviewed beforehand. On top of this, we will also look into options to encrypt any stored user data so that only the rightful recipient is able to access it. Finally, we will put a firewall in place to ensure that no malicious traffic reaches our platform.