The string you provided is a classic payload. It is not a feature of a specific software product but rather a technique used by security researchers and attackers to probe databases for vulnerabilities. Purpose of the Payload
The primary goal of this specific syntax is to returned by the original, legitimate database query. The string you provided is a classic payload
: This command attempts to append a new set of results to the original query's output. The string you provided is a classic payload
: If the number of NULL values does not match the original query's column count, the server usually returns an error (like a 500 Internal Server Error). The string you provided is a classic payload