999999.9' union all select 999,2 and '0'='0 где купить в аптеках, Поиск и заказ лекарств в аптеках Санкт-Петербурга и Ленинградской области онлайн, бронирование и доставка лекарств.
Try to search 999999 9' union all select cast(0x393133353134353632312e39 as char) and '0'0 here.
As a result, they just used `NULL values to populate those columns. the real confusion is in the CONCAT(). They are combining 126, 39, database name as hex
The null character (also null terminator or null byte), abbreviated NUL or NULL, is a control character with the value zero. It is present in many character sets, including ISO/IEC 646 (or ASCII)...
For a style value of NULL, NULL is returned. data_type determines the range.
Note: A NULL value is different from a zero value or a field that contains spaces.
NULL в Системах управления базами данных (СУБД) — специальное значение (псевдозначение), которое может быть записано в поле таблицы базы данных (БД). NULL соответствует понятию «пустое поле», то есть «поле, не содержащее никакого значения».
SQL’s NULL indicates absent data. NULL propagates through expressions and needs distinct comparison operators.
Assigning variables with values during definition is a good practice. A common practice is to assign variables with 0 and pointers with NULL. …