Mega'and/**/extractvalue(1,concat(char(126),md5(1002059835)))and' Today

: Attempts to balance the trailing single quote of the original query to prevent a syntax error that might stop the script from running. Context of Use

: Calculates the MD5 hash of a specific number. In security testing, this is used as a "canary"—if the database error message displays the calculated hash, the tester knows the injection was successful. : Attempts to balance the trailing single quote

: A function used to query XML data. If given an invalid path (which this payload provides), it throws a database error. : A function used to query XML data

: Attempts to close a single-quoted string literal in the original SQL query. The string you've provided is an example of

The string you've provided is an example of a used in automated vulnerability scanning or attacks. It is not a legitimate "proper feature" of a software application; rather, it is designed to exploit security flaws in a database's error-handling mechanism. Breakdown of the Payload

What is SQL Injection? Tutorial & Examples | Web Security Academy