UNION ALL SELECT NULL, *, NULL, NULL FROM email. I understand what this does and why; the hacker needs to create a query that has the same number
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...
CONCAT_NULL_YIELDS_NULL ON INSERT INTO Mytable(StringValue) SELECT COALESCE(MyString + ... ') FROM MyTableOfValues. Further to this I have also checked the database and CONCAT_NULL_YIELDS_NULL = TRUE…
SELECT * FROM table. And then I have to filter out the null values with a php loop.
-1 UNION SELECT * FROM (SELECT * FROM users JOIN users b)a --#1060 - Duplicate column name 'id'
SELECT * FROM `mydata`.`mytable` WHERE CONCAT(<list of columns>) IS NOT NULL. All we are missing now is the list of nullable columns, comma-separated. We're going to use the GROUP_CONCAT function to produce the final statement, which we will execute like this
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько
Пример: SELECT * FROM workers WHERE salary IS NOT NULL.
IS NULL вернёт истину, если операнд имеет значение NULL и ложь, если он им не является.
Предикат IS NULL позволяет проверить отсутствие (наличие) значения в полях таблицы. Использование в этих случаях обычных предикатов сравнения может привести к неверным результатам, так как сравнение со значением NULL дает результат UNKNOWN (неизвестно).