?id=(1)and(SELECT * from db.users)=(1) -- Operand should contain 4 column(s). Then extract the column name. ?id=1 and (1,2,3,4) = (SELECT * from db.users UNION SELECT 1,2,3,4 LIMIT 1) --Column 'id' cannot be null. Method for MySQL 5.
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
Select * FROM Schedule WHERE @ColumnName IS NOT NULL **.
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...
IS NULL вернёт истину, если операнд имеет значение NULL и ложь, если он им не является.
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 reasoning is that a null means "unknown", so the result of any comparison to a null is also "unknown". So you'll get no hit on rows by coding where my_column = null. SQL provides the special syntax for testing if a column is null, via is null and is not null, which is a special condition to test for a...
Пример: SELECT * FROM workers WHERE salary IS NOT NULL.
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).