Learning the database version and structure, which helps in planning further attacks. Prevention

: This is a comment symbol in MySQL/MariaDB. It tells the database to ignore the rest of the original, legitimate code (closing quotes, semicolons, etc.), preventing syntax errors. What is the Goal?

To determine the exact number of columns being retrieved by the original, legitimate query.

If the original query selects 8 columns, this query works. If it selects a different number, the database will return an error, allowing the attacker to deduce the column count by trial and error.