How to block SQL injection on a site written in PHP?

Question

Website security

Answer 1

Write a function sanitizeUrl() that checks urls for malicious insertions with the help of htmlentities()
Prepared statements are also effective: mysqli_prep()
always cast get data to int for integers.

Answer 2

The use of Prepared statements and Santising user inputs

Answer 3

Thanks for the answers, I spent a lot of time doing a functional website with PHP and MySQL without much focus on the security aspect. I will consider your proposals. Thank you

Answer 4

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