Синтаксис: 0xHEX_ЧИСЛО (SM): SELECT CHAR(0x66) (S) SELECT 0x5045 (это не число, а
0x31303235343830303536 is NULL - they are just matching the number of columns in your existing query. If you had SELECT * FROM users and users had 4 columns, the UNION must also have 4 columns. As a result, they just used `NULL values to populate those columns.
Type: UNION query Title: Generic UNION query (NULL) - 18 columns Payload: id=999999.9 UNION ALL SELECT NULL,NULL,NULL,NULL,CONCAT
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...
In SQL, a comparison between a null value and any other value (including another null) using a comparison operator (eg =, !=, <, etc) will result in a null, which is considered as false for the purposes of a where clause (strictly speaking, it's "not true", rather than "false", but the effect is the same).
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null
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».
SELECT 'The list price is ' + CAST(ListPrice AS varchar(12)) AS ListPrice FROM dbo.DimProduct WHERE ListPrice BETWEEN 350.00 AND 400.00
SELECT CONCAT("SQL ", "Tutorial ", "is ", "fun!") AS ConcatenatedString; Try it Yourself ». Definition and Usage. The CONCAT() function adds two or more expressions together. Note: Also look at the CONCAT_WS() function.
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.