-4215) Union All Select 34,34# < 4K >

: The industry standard for web security risks, explaining why injection remains a top threat.

by Halfond, Viegas, and Orso (IEEE Xplore). -4215) UNION ALL SELECT 34,34#

Use -4215) to close an existing integer-based filter or function. : The industry standard for web security risks,

Use UNION ALL SELECT 34,34 to merge a dummy row into the original query results. This helps an attacker determine the number of columns required for a successful data dump. -4215) UNION ALL SELECT 34,34#

(ACM Digital Library).

If you want to practice or learn about this in a controlled environment: