UNION ALL SELECT NULL, *, NULL, NULL FROM email. I understand what this does and why; the hacker needs to create a
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...
Пример: SELECT header, txt FROM news UNION ALL SELECT name, pass FROM members Это позволит объединить
Although Oracle treats zero-length character strings as nulls, concatenating a zero-length character string with another operand always results in the other operand, so null can result only from the concatenation of two null strings.
SELECT id, count(*), count(price>1) FROM usr GROUP BY id. Конечно, в таком виде запрос не сработает.
http://www.harbor.ru/catalogue/cat.php?id=3'+union+all+select+1,(select+concat(0x3d7e3d,ifnull
...Null,null,null,null,null,null,null,null,null,null,null,null,concat
· Using SELECT COUNT(*) or SELECT COUNT(1) (which is what I prefer to use) will return the total of all records returned in the result set regardless of NULL values. · Using COUNT()will count the number of non-NULL items in the specified column (NULL fields...
How do NULL values affect the COUNT function? Here are three different ways to COUNT: Count the…
SELECT City, Country FROM Customers WHERE Country='Germany' UNION ALL SELECT City, Country FROM Suppliers WHERE Country='Germany' ORDER BY City; So, this was all in SQL NULL values. Hope you like our explanation of UNION Clause in SQL.