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.
1' UNION SELECT @--+ #The used SELECT statements have a different number of columns 1' UNION SELECT @,@--+ #The used
qndbq7bbxilyCzFA') UNION ALL SELECT NULL,NULL,NULL,CONCAT(0x716e646271,IFNULL(CAST(grantee AS CHAR),0x20),0x716a716771),NULL FROM INFORMATION_SCHEMA.USER_PRIVILEGES#qjqgq.
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
Используйте NULL в UNION-инъекциях вместо попыток угадать строку, дату, число и прочее. Но будьте аккуратны при слепой инъекции, т.к. вы можете спутать ошибку БД и самого приложения. Некоторые языки, например ASP.NET, выдают ошибку при использовании значения NULL (т.к...
INSERT INTO @DaysAhead (Delta) SELECT 0 UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL
Union select null, null, null, null, null, null -- test all nulls --*/ ). A. DECLARE @ColumnDynamicSQL nvarchar(MAX)
If a null pointer constant is converted to a pointer type, the resulting pointer, called a null pointer, is guaranteed to compare unequal to a pointer to any object or function.”
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.