sql injection "union select null" - CodeProject | To display as
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...
Шпаргалка по SQL инъекциям | DefconRU
...NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULl, NULL-- Можно использовать CAST
Заметка про NULL / Хабр | select col from ttt where col is not null
IS NULL вернёт истину, если операнд имеет значение NULL и ложь, если он им не является.
NULL (Си) — Википедия
NULL в языках программирования Си и C++ — макрос, объявленный в заголовочном файле stddef.h (и других заголовочных файлах).
sql - Count of group for null is always 0 (zero) - Stack Overflow
Select Group, Count(*) From [Data] Group by [Group]. The reason null shows 0 instead of 2 in this case is because each cell is counted as either 1 or null and null + null = null so the total of that group would also be null. However the column type is an integer so it shows up as 0.
Null character - Wikipedia
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.
Обработка значений NULL | Microsoft Docs
Значение Null не является ни пустой строкой (для символьного типа данных или типа данных datetime), ни нулевым значением (для числовых типов данных).A
NULL, '\0' and 0. Help | Forum
Recently, some friends of mine said that NULL, '\0' and 0 are equal because they are all 0-value in ASCII.
Replace Count* with 0 if Null – SQLServerCentral | Forum
I have the following query that may return null if certain dates are selected, I want to display 0 instead of a blank but cannot figure it out: * I removed the date code to make it easier. SELECT ISNULL(COUNT(*), '0') AS thecount.
Null pointers
A null pointer has a reserved value that is called a null pointer constant for indicating that the pointer does not point to any valid object or function. You can use null pointers in the following cases