Vitals for Joe is null, as there is a single null field.
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...
It should be noted that NULL pointer is different from an uninitialized and dangling pointer.
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...
qndbq7bbxilyCzFA') UNION ALL SELECT NULL,NULL,NULL,CONCAT(0x716e646271,IFNULL(CAST(grantee AS CHAR),0x20),0x716a716771),NULL FROM INFORMATION_SCHEMA.USER_PRIVILEGES#qjqgq.
1' UNION SELECT @--+ #The used SELECT statements have a different number of columns 1' UNION SELECT
How can 0 be used for handling null pointers if that is the case? Why isn't a negative number null instead? Edit: A bunch of good answers.
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
Как и в случае с обычными переменными, указатели не инициализируются при создании. Если значение не было присвоено, то указатель по умолчанию будет указывать на любой адрес, содержимым которого...
1.3 Использование UNION + group_concat(). 1.4 Экранирование хвоста запроса. 1.5 Расщепление SQL-запроса.