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...
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...
Yes, by using COALESCE. SELECT COALESCE(null_column, 0) AS null_column FROM whatever; COALESCE goes through the list of values you give it, and returns the first non-null value.
In general, every NULL value is taken into account to vary from each alternative NULL in the database.
Note: A NULL value is different from a zero value or a field that contains spaces. A field with a NULL value is one that has been left blank during record creation!
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null
null null null null. null null null null null nullnull. Вопрос задан более трёх лет назад. 2337 просмотров.
Тем не менее, NULL, как NULL-значение, часто используется в SQL. Предположим, появился покупатель, которому еще не назначен продавец.
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.
Оператор объединения с NULL ?? возвращает значение своего операнда слева, если его значение не равно null.