{keyword}') Union All Select Null,null,null# -

The SQL snippet you've provided, ') UNION ALL SELECT NULL,NULL,NULL# , is a classic payload used to perform a attack.

Specifically, this payload is designed to being returned by a legitimate database query. How This Payload Works {KEYWORD}') UNION ALL SELECT NULL,NULL,NULL#

When an application is vulnerable to SQL injection, an attacker can append their own SQL commands to the original query. The SQL snippet you've provided, ') UNION ALL