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
I have a table with two columns that might be null (as well as some other columns). I would like to count how many rows that have column a, b, both and neither columns set to null. Is this possible with Oracle in one query? Or would I have to create one query for each?
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько
Существуют специальные операторы IS NULL и IS NOT NULL, которые позволяют производить сравнения с NULLами.
Пример: SELECT * FROM workers WHERE salary IS NOT NULL.
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
SELECT column_names FROM table_name WHERE column_name IS NOT NULL; Demo Database.
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