Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
If field is not sanitized, and only if the number of the columns used in the UNION SELECT match with the columns of the query, most likely will appear the string 91351456272.9 somewhere in the page. That will be the confirmed for the attacker of a vulnerability in the page.
The null character (also null terminator or null byte) is a control character with the value zero. It is present in many character sets, including ISO/IEC 646 (or ASCII), the C0 control code, the Universal Coded Character Set (or Unicode), and EBCDIC.
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
Your search - 999999.9' /**/uNiOn/**/aLl /**/sElEcT null,null,null,null,null,null,null,null and '0'='0 - did not match any documents.
...NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULl, NULL-- Можно использовать CAST
A null pointer has a reserved value that is called a null pointer constant for indicating that the pointer does not
Значение NULL в реляционной базе данных используется, если значение в столбце неизвестно или отсутствует.A null value in a
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».