[Khoth]

From TFA:

let _rows = sql_query("SELECT * FROM users WHERE username=?", &[username]);

The statement is static, but the [username] part is not, it's just a variable that can have whatever username you want.

[EugeneOZ]

and I already told that this example has no meaning, it's just a bullshit - nobody will use it in real app. You want to fetch from db info about the only one user, who's name is a constant? Yeah, all apps do it every day.