We are using an advanced rule for systemusername generation where we have below query: CONCAT(
CHAR(FLOOR(65 + RAND() * 26) using UTF8MB4),
CHAR(FLOOR(65 + RAND() * 26) using UTF8MB4),
CHAR(FLOOR(65 + RAND() * 26) using UTF8MB4),
CHAR(FLOOR(65 + RAND...