sql injection "union select null" - CodeProject
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...
SQL using If Not Null on a Concatenation - Stack Overflow
As @Prdp noted, the answer is RDBMS-specific. What is specific is whether the server treats a zero-length string as being equivalent to NULL, which determines whether concatenating a NULL yields a NULL or not. Generally COALESCE is most concise for PostgreSQL-style empty string handling, and...
SQL COUNT « Язык запросов SQL
Синтаксис функции COUNT: SELECT COUNT(expression) FROM table WHERE predicates; Функция COUNT принимает один из нескольких параметров
SQL COUNT(), AVG() and SUM() Functions
SELECT COUNT(column_name) FROM table_name WHERE condition; AVG() Syntax.
oracle - What is the difference between select count(*) and select...
COUNT(*) will include NULLS. COUNT(column_or_expression) won't. This means COUNT(any_non_null_column) will give the same as COUNT(*) of course because there are no NULL values to cause differences. Generally, COUNT(*) should be better because any index can be used...
Ask TOM "Getting multiple counts with a union"
select count(value_x) People from table_a union select count(distinct value_x) People from table_b; We are currently getting: People 24998 23965. We have placed a break on report and computed a sum of count, but that's not really what we want. We would like to see just
Шпаргалка по SQL инъекциям | DefconRU
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько способов не использовать кавычки в запросе, например с помощью CHAR() (MS) и CONCAT() (M). Синтаксис: SELECT 0x457578 (M). В MySQL есть простой способ представления строки в...
25 примеров команды SELECT в MySQL | ИТ Блог.
Вы можете использовать функцию CONCAT в команде SELECT
COUNT (Transact-SQL) - SQL Server | Microsoft Docs
Сюда входят значения NULL и повторяющиеся значения.This includes NULL values and duplicates.