{keyword}' Union All Select Null,null,null,null,null,null,null,null,null,null-- | Ebfu

: Comments out the rest of the legitimate SQL code so it doesn't execute and cause an error.

: Used to match the number of columns in the original table. Attackers add these one by one until the error message disappears. : Comments out the rest of the legitimate

: Combines the results of the original query with a new query. : Comments out the rest of the legitimate

Discuss the difference between and Blind SQL injection. : Comments out the rest of the legitimate

Validating and sanitizing all user-provided data is a secondary layer of defense. If you'd like to dive deeper, I can: