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 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...
11223344) UNION SELECT NULL,NULL,NULL,NULL WHERE 1=2 –- Если нет ошибки, значит синтаксис верный, т.е. используется MS SQL Server.
MYSQL Union Based. Detect columns number.
As shown below, I need not null values to be at the start of all output fields.
SELECT * FROM schedule WHERE ((all)) IS NOT NULL. Do I just remove the all and go..?
Логические операции и NULL. Обычно, состояние НЕИЗВЕСТНО обрабатывается так же, как ЛОЖЬ. Например, если вы выбираете строки из таблицы и вычисление условия x = NULL в предложении WHERE дало результат НЕИЗВЕСТНО, то вы не получите ни одной строки.
select cast (2000 as type of quint) from rdb$database select cast (2000 as int) from rdb$database. If TYPE OF is used with a (VAR)CHAR type, its character.
SELECT col1 AS col FROM yourtable UNION SELECT col2 AS col FROM yourtable UNION -- ... UNION SELECT coln AS col FROM yourtable ) T1 WHERE col IS NOT NULL. And I agre with Martin that if you need to do this then you should probably change your database design.
UNION позволяет объединять результаты в один от нескольких выражений SELECT. Конструируем наш запрос с UNION