If you had SELECT * FROM users and users had 4 columns, the UNION must also have 4 columns. As a result, they just used `NULL values to populate those columns.
So we have a search field on our website, and I save all of the search terms to a database table. I brought up the search term table today and noticed some weird searches...
SELECT neededfield, CONCAT(firstname, ' ', lastname) as firstlast FROM users WHERE CONCAT(firstname, ' ', lastname) = "Bob Michael Jones". Your alias firstlast is not available in the where clause of the query unless you do the query as a sub-select.
21 and (select 1 from (select count(*),concat((select(select concat(cast(column_name as char),0x7e)) from information_schema.columns where table_name=0x73657474696e6773 limit 2,1),floor(rand(0)*2))x from information_schema.tables group by x)a).
CONCAT() returns NULL if any argument is NULL.
Синтаксис: ; (S): SELECT * FROM members; DROP members-- Один запрос закончился
SELECT * FROM news WHERE id_news = 5. Но если злоумышленник передаст в качестве параметра id строку -1 OR 1=1 (например, так
SELECT pname FROM posts UNION SELECT dname FROM departments; С помощью UNION мы объединяем два запроса SQL SELECT и выводим их
Example. SELECT City FROM Customers UNION SELECT City FROM Suppliers ORDER BY City