This post is part of the SQL: Zero to Ninja series. You built a login form. A user types their email, you look them up, and you log them in. Works great. Then one day a stranger types something weird into that email box, and suddenly they are reading every user's data, or your users table is just... gone. That is SQL injection, and it is one of the oldest and nastiest bugs on the web. The good news: once you see how it happens, fixing it is easy and you never have to fear it again. The idea in one line SQL injection happens when you glue user input straight into your query as text, so the user can sneak in their own SQL, and the fix is to send the input as data , never as part of the query. The metaphor: a form letter with blanks Imagine a form letter: Dear __________, your order #_______ is ready. Enter fullscreen mode Exit fullscreen mode You fill the blanks with a name and a number. The sentence shape never changes. The blanks are just blanks. Safe.…