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 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
11223344) UNION SELECT NULL,NULL,NULL,NULL WHERE 1=2 –- Если нет ошибки, значит синтаксис верный, т.е. используется MS SQL
Пример: SELECT * FROM workers WHERE salary IS NOT NULL.
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
returns non null values in group */ SELECT COUNT(Col1) FROM ##TestData; Because of this, COUNT, DISTINCT, and NULLs have a special relationship with each other
A field with a NULL value is a field with no value. If a field in a table is optional, it is possible to insert a new record or update a
The first to see what might of happened here, the ‘null’ name bit, is the following command
I've been asked about counting NULL values several times so I'm going to blog about it in hopes others will be helped by this explanation of NULL values in
Разрешение значений NULL в определениях столбцов вводит в приложение логику трех значений.Allowing null