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...
...null, null, null, null from information_schema.tables. for a small database containing three tables. this
UNION ALL SELECT NULL, *, NULL, NULL FROM email. I understand what this does and why; the hacker needs to create a query that has the same number of columns as the query it's being merged with, and shifted around the * to make sure the emails are displayed.
If a null pointer constant is converted to a pointer type, the resulting pointer, called a null pointer, is guaranteed to compare unequal to a pointer to any object or function.”
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
999999.9+union+all+select+%27R3DM0V3_hvj_injection',null
The IS NULL operator is used to test for empty values (NULL values). The following SQL lists all customers with a NULL value in the "Address" field
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».
Be as detailed as possible. Community members, including developers, shall try and help.
NULL не является ни пустой строкой (для типов данных character или datetime), ни