Are you for security flaws, or did you come across this in your site's traffic logs?
The random-looking string ( qbqvq...qqbqq ) is often used by automated security scanners or attackers as a "canary" to see if the injected text is reflected back in the application's response, confirming the vulnerability.
It looks like you've shared a snippet of a attempt. Specifically, this string is designed to test for vulnerabilities in a database by using a UNION ALL SELECT statement to append data from a new query to the results of the original one.
