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...
select a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f from table3.
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.
Note: A NULL value is different from a zero value or a field that contains spaces.
Number of null-s on change between passed and failed queries is the one attacker looks for.
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...
E.g. null + null + 1 = 1 null + null + null = null. The problem is that the first expression yields null.
Thus even though you have casted null to match ssn's datatype bigint, you must give it an alias as shown below.
Union select null, null, null, null, null, null -- test all nulls --*/ ). A. DECLARE @ColumnDynamicSQL nvarchar(MAX)
R language supports several null-able values and it is relatively important to understand how these