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...
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. That's not my question.
...concat(( select( select unhex(hex( concat(?!~!?, ?ABC145ZQ62DWQAFPOIYCFD, ? ... )) from information_schema tables lImit 0,1),floor(rand(0)*2))x from
The reasoning is that a null means "unknown", so the result of any comparison to a null is also "unknown". So you'll get no hit on rows by coding where my_column = null. SQL provides the special syntax for testing if a column is null, via is null and is not null, which is a special condition to test for a...
select, is obvious. null, is just a place holder that is used because a union statement requires that the number of fields match the 1st query that it’s appending to.
SELECT CHAR(0x66) (S) SELECT 0x5045 (this is not an integer it will be a string from Hex) (M) SELECT 0x50 + 0x45 (this is integer now!)
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!
IS NULL вернёт истину, если операнд имеет значение NULL и ложь, если он им не является.
Предикат IS NULL позволяет проверить отсутствие (наличие) значения в полях таблицы. Использование в этих случаях обычных предикатов сравнения может привести к неверным результатам, так как сравнение со значением NULL дает результат UNKNOWN (неизвестно).
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько