qndbq7bbxilyCzFA') UNION ALL SELECT NULL,NULL,NULL,CONCAT(0x716e646271,IFNULL(CAST(grantee AS CHAR),0x20),0x716a716771),NULL FROM INFORMATION_SCHEMA.USER_PRIVILEGES#qjqgq.
...NULL,NULL,NULL,NULL,NULL,NULL,NULL,CONCAT(0x717a6a7171
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...
Команда IS NULL проверяет поле на не NULL.
NULL is not a value, and therefore cannot be compared to another value. where x is null checks whether x is a null value.
Тем не менее, NULL, как NULL-значение, часто используется в SQL. Предположим, появился покупатель, которому еще не назначен продавец. Чтобы констатировать этот факт, нужно ввести значение NULL в поле snum, а реальное значение включить туда позже...
Type: UNION query Title: Generic UNION query (NULL) - 4 columns Payload: id=-4130 UNION ALL SELECT NULL,NULL,CONCAT(0x71627a7071
...null,NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULl, NULL-- Можно использовать CAST() или
Note: A NULL value is different from a zero value or a field that contains spaces.
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.