Mega'and(select*from(select Sleep(2))a/**/union/**/select 1)=' -

: Access entire tables of user info, emails, and hashed passwords.

The string you provided is a classic example of a payload designed to test for vulnerabilities in a web application's database. : Access entire tables of user info, emails,

: This is the core of the attack.

: This part attempts to "break out" of a text string in the database query. The single quote ( ' ) is used to end the intended data input so that the database starts reading the following text as a command. : Access entire tables of user info, emails,

: These are comment tags used to bypass basic security filters that might block spaces. : Access entire tables of user info, emails,