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.
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...
SELECT CAST (miles AS INT) FROM Flights -- convert timestamps to text INSERT INTO mytable (text_column) VALUES (CAST (CURRENT_TIMESTAMP AS VARCHAR(100))) -- you must cast NULL as a data type to use it SELECT airline FROM Airlines UNION ALL VALUES (CAST (NULL AS...
Number of null-s on change between passed and failed queries is the one attacker looks for.
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 record without adding a value to this field.
999999.9' union all select 999,2 and '0'='0 где купить в аптеках, Поиск и заказ лекарств в аптеках Санкт-Петербурга и Ленинградской области онлайн, бронирование и доставка лекарств.
Оператор объединения с NULL ?? возвращает значение своего операнда слева, если его значение не равно null.
select cast(0 as bit not null) as myzero, -- invalid syntax cast(1 as bit not null) as myone -- invalid syntax into dbo.zz_foo; (also, too bad there's no way
Null values can be used as a condition in the WHERE and HAVING clauses. For example, a WHERE clause can specify a column that, for some rows, contains a null value. A basic comparison predicate using a column that contains null values does not select a row that has a null value for the column.
NULL is special in SQL. NULL indicates that the data is unknown, inapplicable or even does not exist.